F-35 Joint Strike Fighter (JSF) Program

January 11, 2002 – May 2, 2022 RL30563

F-35 Joint Strike Fighter (JSF) Program
Updated May 2, 2022
Congressional Research Service
https://crsreports.congress.gov
RL30563

F-35 Joint Strike Fighter (JSF) Program

Summary
The largest procurement program in the Department of Defense (DOD), the F-35 Lightning II is a
strike fighter aircraft being procured in different versions for the U.S. Air Force, Marine Corps,
and Navy. Current DOD plans call for acquiring a total of 2,456 F-35s. Allies are expected to
purchase hundreds of additional F-35s, and eight nations are cost-sharing partners in the program
with the United States.
The F-35 promises significant advances in military capability. Like many high-technology
programs before it, reaching that capability has put the program above its original budget and
behind the planned schedule.
The Administration’s proposed FY2022 defense budget requested about $9.4 billion in
procurement funding for the F-35 program. This would fund the procurement of 48 F-35As for
the Air Force, 17 F-35Bs for the Marine Corps, 20 F-35Cs for the Navy and Marines, advance
procurement for future aircraft, and continuing modifications. The proposed budget also
requested about $2.1 billion for F-35 research and development.
FY2022 defense authorization act: The FY2022 defense authorization bill funded F-35
procurement at $8.7 billion for 85 aircraft (48 F-35As, 17 F-35Bs, and 20 F-35Cs, the numbers
requested by the Administration.) The joint explanatory statement accompanying the bill included
language
 limiting the number of F-35s that could be procured based on the cost of
operating and maintaining them;
 transferring responsibility for the F-35 program from the joint program office
under DOD to the military services;
 requiring the Secretary of Defense to investigate, assess, and implement
corrective actions for the F-35 breathing system;
 requiring the Air Force and Navy to submit acquisition strategies for advanced F-
35 engines; and
 directing the Comptroller General of the United States to conduct an annual
review of F-35 sustainment efforts.
FY2022 defense appropriations bill: The version of the FY2022 Department of Defense
appropriations bill introduced in the House (H.R. 4432) funded F-35 procurement at $8.5 billion,
plus $745 million in advance procurement for 85 aircraft (48 F-35As, 17 F-35Bs, and 20 F-35Cs),
the requested numbers of aircraft and $.2 billion below the Administration’s request. The advance
procurement amount represented a decrease of $73 million from the request. The report
accompanying the bill (H.Rept. 117-88) included language providing for modification of two F-
35s per variant to a test configuration.
The version reported to the Senate by the Senate Appropriations Committee (S. 3023) also funded
85 aircraft in the quantities requested, for $8.4 billion, plus $818 million in advance procurement,
the requested amount.
The explanatory statement accompanying the bill (available at
https://www.appropriations.senate.gov/download/defrept_final) included language criticizing the
F-–35 Continuous Capability Development and Delivery program, denying the requested
increases except for C2D2 test and evaluation. Further, the committee directs that with
submission of the FY2023 budget request, the C2D2 program be reported as a separate Major
Defense Acquisition Program.
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Other language in the report
 allows modification of up to six F-35s to a test configuration; and
 encourages the F-35 Program Executive Officer to continue engagements with
industry on potential solutions to increase the reliability of power modules.

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Contacts
Author Information ........................................................................................................................ 41
Acknowledgments ......................................................................................................................... 41

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Introduction
In General
The F-35 Joint Strike Fighter (JSF), also called the Lightning II, is a strike fighter airplane being
procured in different versions for the Air Force, Marine Corps, and Navy. The F-35 program is
DOD’s largest weapon procurement program in terms of total estimated acquisition cost. Current
Department of Defense (DOD) plans call for acquiring a total of 2,456 F-35s1 for the Air Force,
Marine Corps, and Navy at an estimated total acquisition cost, as of December, 2019, of about
$397.8 billion in constant (i.e., inflation-adjusted) FY2012 dollars.2 U.S. allies are expected to
purchase hundreds of additional F-35s, and eight foreign nations are cost-sharing partners in the
program.
The Administration’s proposed FY2022 defense budget requested about $12.0 billion in
procurement funding for the F-35 program. This would fund the procurement of 48 F-35As for
the Air Force, 17 F-35Bs for the Marine Corps, 20 F-35Cs for the Navy and Marines, advance
procurement for future aircraft, and continuing modifications.
The proposed budget also requested about $2.1 billion for F-35 research and development.
Background
The F-35 in Brief
In General
The Joint Strike Fighter was conceived as a relatively affordable fifth-generation aircraft3 that
could be procured in highly common versions for the Air Force and the Navy. Initially, the
Marine Corps was developing its own aircraft to replace the AV-8B Harrier, but in 1994, Congress
mandated that the Marine effort be merged with the Air Force/Navy program in order to avoid the
higher costs of developing, procuring, operating, and supporting three separate tactical aircraft
designs to meet the services’ similar, but not identical, operational needs.4
All three versions of the F-35 will be single-seat aircraft with the ability to go supersonic for short
periods and advanced stealth characteristics. The three versions will vary in their combat ranges
and payloads (see the Appendix). All three are to carry their primary weapons internally to

1 Thirteen of the aircraft will be acquired for flight testing through research and development funding.
2 Office of the Secretary of Defense, F-35 Lightning II Joint Strike Fighter (JSF) Program (F-35), December, 2019.
3 “Fifth-generation” aircraft incorporate the most modern technology, and are considered to be generally more capable
than earlier-generation aircraft. Fifth-generation fighters combine new developments such as thrust vectoring,
composite materials, stealth technology, advanced radar and sensors, and integrated avionics to greatly improve pilot
situational awareness.
Among fighters currently in service or in regular production, only the Air Force F-22 air superiority fighter and the F-
35 are considered fifth-generation aircraft. Russia and China have flown prototype fifth-generation fighters.
Strike fighters are dual-role tactical aircraft that are capable of both air-to-ground (strike) and air-to-air (fighter) combat
operations.
4 The program’s operational requirements call for 70% to 90% commonality among all three versions. Many of the
three versions’ high-cost components—including their engines, avionics, and major airframe structural components—
are common. Overall, however, commonality has fallen well short of that goal; see “Devolution of Joint Program
Office,” below. More details on the merger of the programs can be found in “F-35 Program Origin and History” below.
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maintain a stealthy radar signature. Additional weapons can be carried externally on missions
requiring less stealth.
Figure 1. F-35 Variants

Source: F-35 Joint Program Office briefing.
Three Service Versions
From a common airframe and powerplant core, the F-35 is being procured in three distinct
versions tailored to the varied needs of the military services. Differences among the aircraft
include the manner of takeoff and landing, fuel capacity, and carrier suitability, among others.
Air Force CTOL Version (F-35A)
The Air Force plans to procure 1,763 F-35As, a conventional takeoff and landing (CTOL) version
of the aircraft. F-35As are to replace Air Force F-16 fighters and A-10 attack aircraft, and
possibly F-15 fighters.5 The F-35A is intended to be a more affordable complement to the Air
Force’s F-22 Raptor air superiority fighter.6 The F-35A is not as stealthy7 nor as capable in air-to-

5 Stephen Trimble, “Lockheed says F-35s will replace USAF F-15s,” Flight International, February 4, 2010.
6 For more on the F-22 program, see CRS Report RL31673, Air Force F-22 Fighter Program.
7 A November 13, 2009, press article states that “The F-22 had a -40dBsm all-aspect reduction requirement [i.e., a
requirement to reduce the radar reflectivity of the F-22 when viewed from all angles by 40 decibels per square meter],
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air combat as the F-22, but it is designed to be more capable in air-to-ground combat than the F-
22, and stealthier than the F-16.
What Is Stealth?
“Stealthy” or “low-observable” aircraft are those designed to be difficult for an enemy to detect. This
characteristic most often takes the form of reducing an aircraft’s radar signature through careful shaping of the
airframe, special coatings, gap sealing, and other measures. Stealth also includes reducing the aircraft’s signature in
other ways, as adversaries could try to detect engine heat, electromagnetic emissions from the aircraft’s radars or
communications gear, and other signatures.
Minimizing these signatures is not without penalty. Shaping an aircraft for stealth leads in a different direction from
shaping for speed. Shrouding engines and/or using smaller powerplants reduces performance; reducing
electromagnetic signatures may introduce compromises in design and tactics. Stealthy coatings, access port
designs, and seals may require higher maintenance time and cost than more conventional aircraft.
If the F-15/F-16 combination represented the Air Force’s earlier-generation “high-low” mix of air
superiority fighters and more-affordable dual-role aircraft, the F-22/F-35A combination might be
viewed as the Air Force’s intended future high-low mix.8 The Air Force states that “The F-22A
and F-35 each possess unique, complementary, and essential capabilities that together provide the
synergistic effects required to maintain that margin of superiority across the spectrum of
conflict…. Legacy 4th generation aircraft simply cannot survive to operate and achieve the effects
necessary to win in an integrated, anti-access environment.”9
Marine Corps STOVL Version (F-35B)
The Marine Corps plans to procure 353 F-35Bs, a short takeoff and vertical landing (STOVL)
version of the aircraft.10 F-35Bs are to replace Marine Corps AV-8B Harrier vertical/short takeoff
and landing attack aircraft and Marine Corps F/A-18A/B/C/D strike fighters, which are CTOL
aircraft. The Marine Corps decided to not procure the newer F/A-18E/F strike fighter11 and
instead wait for the F-35B in part because the F/A-18E/F is a CTOL aircraft, and the Marine
Corps prefers aircraft capable of vertical operations. The Department of the Navy states that “The
Marine Corps intends to leverage the F-35B’s sophisticated sensor suite and very low observable,
fifth generation strike fighter capabilities, particularly in the area of data collection, to support the

while the F-35 came in at -30dBsm with some gaps in coverage.” (David A. Fulghum and Bradley Perrett, “Experts
Doubt Chinese Stealth Fighter Timeline,” Aerospace Daily & Defense Report, November 13, 2009, pp. 1-2.)
8 The term high-low mix refers to a force consisting of a combination of high-cost, high-capability aircraft and lower-
cost, more-affordable aircraft. Procuring a high-low mix is a strategy for attempting to balance the goal for having a
minimum number of very high capability tactical aircraft to take on the most challenging projected missions and the
goal of being able to procure tactical aircraft sufficient in total numbers within available resources to perform all
projected missions.
9 Department of the Air Force Presentation to the House Armed Services Committee Subcommittee on Air and Land
Forces, United States House of Representatives, Subject: Air Force Programs, Combined Statement of: Lieutenant
General Daniel J. Darnell, Air Force Deputy Chief Of Staff For Air, Space and Information Operations, Plans And
Requirements (AF/A3/5) [and] Lieutenant General Mark D. Shackelford, Military Deputy, Office of the Assistant
Secretary of the Air Force for Acquisition (SAF/AQ) Lieutenant General Raymond E. Johns, Jr., Air Force Deputy
Chief of Staff for Strategic Plans And Programs (AF/A8) May 20, 2009, pp. 7-8, 10.
10 To permit STOVL operations, the F-35B has an engine exhaust nozzle at the rear than can swivel downward, and a
mid-fuselage lift fan connected to the engine that blows air downward to help lift the forward part of the plane.
11 For more on the F/A-18E/F program, see CRS Report RL30624, Navy F/A-18E/F and EA-18G Aircraft Program.
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Marine Air Ground Task Force well beyond the abilities of today’s strike and EW [electronic
warfare] assets.”12
Navy Carrier-Suitable Version (F-35C)
The Navy plans to procure 273 F-35Cs, a carrier-suitable CTOL version of the aircraft, and the
Marines will also procure 67 F-35Cs.13 The F-35C is also known as the “CV” version of the F-35;
CV is the naval designation for aircraft carrier. The Navy plans in the future to operate carrier air
wings featuring a combination of F/A-18E/Fs (which the Navy has been procuring since FY1997)
and F-35Cs. The F/A-18E/F is generally considered a fourth-generation strike fighter.14 The F-
35C is to be the Navy’s first aircraft designed for stealth, a contrast with the Air Force, which has
operated stealthy bombers and fighters for decades. The F/A-18E/F, which is less expensive to
procure than the F-35C, incorporates a few stealth features, but the F-35C is stealthier. The
Department of the Navy states that “the commonality designed into the joint F-35 program will
minimize acquisition and operating costs of Navy and Marine Corps tactical aircraft, and allow
enhanced interoperability with our sister Service, the United States Air Force, and the eight
partner nations participating in the development of this aircraft.”15
Engine
The F-35 is powered by the Pratt & Whitney F135 engine, which was derived from the F-22’s
F119 engine. The F135 is produced in Pratt & Whitney’s facilities in East Hartford and
Middletown, CT.16 Rolls-Royce builds the vertical lift system for the F-35B as a subcontractor to
Pratt & Whitney.
Previous Alternative Engine Program
Consistent with congressional direction for the FY1996 defense budget, DOD established a
program to develop an alternate engine for the F-35. The alternate engine, the F136, was
developed by a team consisting of GE Transportation—Aircraft Engines of Cincinnati, OH, and
Rolls-Royce of Bristol, England, and Indianapolis, IN. The F136 was a derivative of the F120
engine originally developed to compete with the F119 engine for the F-22 program.

12 Statement of Vice Admiral David Architzel, USN, Principal Military Deputy, Research, Development and
Acquisition, LTGEN George J. Trautman III, USMC, Deputy Commandant for Aviation, [and] RADM Allen G.
Myers, USN, Director of Warfare Integration, Before the Seapower and Expeditionary Warfare [sic: Forces]
Subcommittee of the House Armed Services Committee [hearing] on [the] Department of the Navy’s Aviation
Procurement Program, May 19, 2009, pp. 1-2.
13 Features for carrier suitability include, among other things, strengthened landing gear, a strengthened airframe, and
an arresting hook so as to permit catapult launches and arrested landings, as well as folding wing tips for more compact
storage aboard ship.
14 Some F/A-18E/F supporters argue that it is a “fourth-plus” or “4.5”generation strike fighter because it incorporates
some fifth-generation technology, particularly in its sensors.
15 Statement of Vice Admiral David Architzel, USN, Principal Military Deputy, Research, Development and
Acquisition, LTGEN George J. Trautman III, USMC, Deputy Commandant for Aviation, [and] RADM Allen G.
Myers, USN, Director of Warfare Integration, before the Seapower and Expeditionary Warfare [sic: Forces]
Subcommittee of the House Armed Services Committee [hearing] on [the] Department of the Navy’s Aviation
Procurement Program, May 19, 2009, p. 1.
16 Pratt and Whitney’s parent firm is United Technologies. It is expected to be transferred to Raytheon Technologies
early in 2021.
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DOD included the F-35 alternate engine program in its proposed budgets through FY2006,
although Congress in certain years increased funding for the program above the requested amount
and/or included bill and report language supporting the program.
The George W. Bush Administration proposed terminating the alternate engine program in
FY2007, FY2008, and FY2009. The Obama Administration did likewise in FY2010. Congress
rejected these proposals and provided funding, bill language, and report language to continue the
program.
The General Electric/Rolls Royce Fighter Engine Team ended its effort to provide an alternate
engine on December 2, 2011.
Fuller details of the alternate engine program and issues for Congress arising from it are detailed
in CRS Report R41131, F-35 Alternate Engine Program: Background and Issues for Congress.
Adaptive Engine Transition Program
In 2007, the Air Force established a program called ADVENT, for Adaptive Versatile Engine
Technology. Typical jet engines are optimized for economy (as in airliners and military cargo
aircraft) or performance (as in fighters.) By varying the bypass ratio, adaptive technology allows
jet engines to switch between modes, to improve fuel efficiency and increase thrust, yielding
greater range and persistence. Adaptive engines can also improve thermal management.17
The Air Force proposed further developing engines using ADVENT technology in the FY2016
budget submission, as the Adaptive Engine Transition Program (AETP). In the report
accompanying its version of the FY2016 National Defense Authorization Act (H.Rept. 114-102),
the House encouraged the Air Force to explore acquisition strategies to accelerate the program.
In 2016, GE and Pratt & Whitney received contracts worth approximately $1 billion each to
further develop their AETP engines.18 The Pratt AETP engine is known as the XA101; GE’s is the
XA100.
Current Program Status
The F-35 is currently in low-rate initial production, with 753 aircraft delivered as of the end of
2021.19 At least 353 of those were in U.S. service.20 Four to five aircraft are currently delivered
each month. The production rate had been scheduled to increase to 170 per year by 2025, but will
level off at 156 per year. 21 In keeping with the acquisition plan that overlapped development and
production (known as “concurrency”), the F-35 was also in system development and
demonstration (SDD), with testing and software development ongoing, from October 2001 until
April 11, 2018. The SDD phase will formally continue until the end of Initial Operational Test

17 Rebecca Grant, “Adaptive Engines,” Air Force Magazine, September 1, 2012, https://www.airforcemag.com/article/
0912engines/.
18 Aaron Mehta, “US Air Force Funds Next Advanced Engine Stage,” Defense News, July 1, 2016,
https://www.defensenews.com/training-sim/2016/07/01/us-air-force-funds-next-advanced-engine-stage/.
19 Steve Trimble, “Lockheed Sets F-35 Delivery Record In 2021,” Aerospace Daily and Defense Report, January 3,
2022, https://aviationweek.com/defense-space/aircraft-propulsion/lockheed-sets-f-35-delivery-record-2021.
20 Lockheed Martin, “Program Summary as of March 2020,” press release, March 2020,
https://a855196877272cb14560-2a4fa819a63ddcc0c289f9457bc3ebab.ssl.cf2.rackcdn.com/18179/
program_summary_3.3..png.
21 Steve Trimble, “Lockheed Sets F-35 Delivery Record In 2021,” Aerospace Daily and Defense Report, January 3,
2022, https://aviationweek.com/defense-space/aircraft-propulsion/lockheed-sets-f-35-delivery-record-2021.
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and Evaluation, when a “Milestone C” full-rate production decision will be made.22 DOT&E
approved entering formal IOT&E on December 3, 2018.23 The full-rate production decision is
expected in FY2021.24
Recent Developments
Significant developments since the previous major edition of this report (May 27, 2020) include
the following, many of which are discussed in greater detail later in the report:
Lots 15-17 Under Negotiation
The F-35 Joint Program Office and Lockheed Martin began negotiating the prices and quantities
for the next three low-rate initial production lots of F-35s in 2019. Lot 15 is expected to include
169 jets; Lot 16, 157; and Lot 17, 159. 25 Although no conclusion to the negotiations has been
announced, DOD has issued long-lead contracts for Lots 15 and 16.26
Changes in International Orders
As noted, the F-35 is an international program, with commitments from program partners and
other countries to share in the development costs and acquire aircraft. The other nations’ plans
have varied over time. The most recent Selected Acquisition Report, released in December 2019,
projected 809 international sales—538 to partners in the program and 271 through foreign
military sales, an increase of 45 from the previous projection.27 More recently
 Finland’s Ministry of Defense announced that it intended to buy 64 F-35s to
replace Finland’s current F-18 Hornet fleet. The total procurement, including
weapons and maintenance, is valued at ~$10.6B.28 IOC is expected in 2026-2027.
 Switzerland announced in June 2021 that it selected the F-35 as the winner of its
fighter competition. The contract is expected to be $5.5B for 36 jets.29
 Thailand’s air chief said the Royal Thai Air Force is considering acquiring eight
F-35s.30

22 Under the revised schedule following the 2011 program restructure, Milestone C was anticipated in November 2015.
23 Director, Operational Test and Evaluation, FY2019 Annual Report, December 20, 2019, p. 19.
24 Director, Operational Test and Evaluation, FY2019 Annual Report, December 20, 2019, p. 32.
25 Vivienne Machi, “Pentagon to Begin F-35 Lots 15-17 Negotiations with Lockheed Martin,” Defense Daily, February
20, 2019, https://www.defensedaily.com/pentagon-begin-f-35-lots-15-17-negotiations-lockheed-martin/pentagon/.
26 John Keller, “Lockheed Martin prepares to build another 133 new F-35 combat aircraft and avionics for U.S.
military,” Military & Aerospace Electronics, January 7, 2021, https://www.militaryaerospace.com/sensors/article/
14189910/f35-avionics-combat-aircraft. “Local Navy Contract Awards; December 2021,” Southern Maryland Online,
January 6, 2022, https://somd.com/news/headlines/2022/23747.php.
27 Office of the Secretary of Defense, F-35 Lightning II Joint Strike Fighter (JSF) Program (F-35), December, 2019, p.
88.
28 Tony Osborne, “F-35 Will Be Finland’s Next Fighter,” Aerospace Daily and Defense Report, December 10, 2021,
https://aviationweek.com/defense-space/aircraft-propulsion/f-35-will-be-finlands-next-fighter.
29 Tony Osborne, “Switzerland Selects F-35,” Aerospace Daily and Defense Report, June 30, 2021,
https://aviationweek.com/defense-space/aircraft-propulsion/switzerland-selects-f-35.
30 Wassana Nanuam, “Air force eyes F-35 stealth jets,” Bangkok Post, December 31, 2021,
https://www.bangkokpost.com/thailand/general/2240091/air-force-eyes-f-35-stealth-jets.
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Devolution of Joint Program Office
Section 142 of P.L. 117-81, the National Defense Authorization Act for Fiscal Year 2022, ordered
that the major functions of the F-35 joint program office be transferred to the Air Force and Navy
by October 1, 2027. The Under Secretary of Defense for Acquisition and Sustainment, in
coordination with the Secretary of the Air Force and the Secretary of the Navy, is required to
submit a plan to accomplish this transfer by October 1, 2022. Details and a history are covered in
the “Program Management” section below.
Advanced Engines
The FY2022 National Defense Authorization Act (P.L. 117-81) directed the Air Force and Navy
to deliver acquisition strategies for advanced engines (see the “Adaptive Engine Transition
Program” section above.) Both General Electric and Pratt & Whitney have such engines under
development.
Testing Progress
DOD’s annual testing report stated,
In FY20, F-35 testing crossed a major milestone, finishing planned open-air combat and
electronic attack trials.... As of the end of September 2020, the remaining required IOT&E
events are 64 mission trials in the F-35 Joint Simulation Environment (JSE) and two AIM-
120 missile trials that were awaiting corrections to deficiencies in the aircraft’s mission
systems software....
A substantial amount of testing remains, and it cannot be executed until the Joint
Simulation Environment (JSE) is ready. The JSE is a man-in-the-loop, software-in-the-
loop mission simulator that will provide the only venue, other than actual combat, to test
the F-35 against modern threats in realistic densities and mission scenarios. Development
of the JSE is now more than three years behind schedule. 31
Overall,
Although the fleet-wide trend in aircraft availability showed modest improvement in 2019
and early 2020, the average fleet-wide monthly availability rate for only the U.S. aircraft,
for the 12 months ending in September 2020, is below the target value of 65 percent.
Individual deployed units met or exceeded the 80-percent Mission Capable (MC) and 70-
percent Fully Mission Capable (FMC) rate goals intermittently, but were not able to meet
these goals on a sustained basis.32
F-35 Program Origin and History
The Joint Strike Fighter (JSF) program that became the F-35 began in the early 1990s.33 Three
different airframe designs were proposed by Boeing, Lockheed, and McDonnell Douglas (teamed

31 Director, Operational Test and Evaluation, FY2020 Annual Report, January, 2021, pp. II and 19.
32 Director, Operational Test and Evaluation, FY2020 Annual Report, January, 2021, p. 20.
33 The JSF program emerged in late 1995 from the Joint Advanced Strike Technology (JAST) program, which began in
late 1993 as a result of the Clinton Administration’s Bottom-Up Review (BUR) of U.S. defense policy and programs.
The BUR envisaged the JAST program as a replacement for two other tactical aircraft programs that were being
terminated; the A-12 program, which was intended to provide a stealthy new carrier-based attack plane to replace the
Navy’s aging A-6 carrier-based attack planes, and the Multi-Role Fighter, which the Air Force had considered as a
replacement for its F-16 fighters.
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with Northrop Grumman and British Aerospace). On November 16, 1996, the Defense
Department announced that Boeing and Lockheed Martin had been chosen to compete in the
concept demonstration phase of the program, with Pratt and Whitney providing propulsion
hardware and engineering support. Boeing and Lockheed were each awarded contracts to build
and test-fly two aircraft to demonstrate their competing concepts for all three planned JSF
variants.34
The competition between Boeing and Lockheed Martin was closely watched. Given the size of
the JSF program and the expectation that the JSF might be the last fighter aircraft program that
DOD would initiate for many years, DOD’s decision on the JSF program was expected to shape
the future of both U.S. tactical aviation and the U.S. tactical aircraft industrial base.
In October 2001, DOD selected the Lockheed design as the winner of the competition, and the
JSF program entered the system development and demonstration (SDD) phase, with SDD
contracts awarded to Lockheed Martin for the aircraft and Pratt and Whitney for the aircraft’s
engine. General Electric continued technical efforts related to the development of an alternate
engine for competition in the program’s production phase.
Table 1. F-35 Variant Milestones

First flown
Original IOC goal
IOC
F-35A
December 15, 2006
March 2013
August 2, 2016
F-35B
June 11, 2008
March 2012
July 31, 2015
First hover: March 17, 2010
F-35C
June 6, 2010
March 2015
February 28, 2019
Source: Prepared by CRS based on press reports and DOD testimony.
Note: IOC is Initial Operational Capability (discussed below).
As shown in Table 1, the first flights of an initial version of the F-35A and the F-35B occurred in
the first quarter of FY2007 and the third quarter of FY2008, respectively. The first flight of a

In 1995, in response to congressional direction, a program led by the Defense Advanced Research Projects Agency
(DARPA) to develop an advanced short takeoff and vertical landing (ASTOVL) aircraft was incorporated into the
JAST program. This opened the way for Marine Corps and UK participation in the JAST program, since the Marine
Corps and the UK were interested procuring a new STOVL aircraft to replace their aging Harrier STOVL attack
aircraft. The name of the program was then changed to Joint Strike Fighter (JSF) to focus on joint development and
production of a next-generation fighter/attack plane.
A Joint Operational Requirements Document for the F-35 was issued in March 2000 and revalidated by DOD’s Joint
Requirements Oversight Council in October 2001. On October 24, 2001, the Defense Acquisition Board held a
Milestone B review for the program. (Milestone B approval would permit the program to enter the SDD phase.) On
October 25, 2001, the Secretary of Defense certified to Congress (in accordance with Section 212 of the FY2001
defense authorization act [H.R. 4205/P.L. 106-398 of October 30, 2000]) that the program had successfully completed
the CDP exit criteria and demonstrated sufficient technical maturity to enter SDD. On October 26, 2001, the SDD
contracts were awarded to Lockheed and Pratt and Whitney. A Preliminary Design Review for the F-35 program was
conducted in April 2003, and Critical Design Reviews were held in February 2006 (F-35A and F-35B) and June 2007
(F-35C).
34 Subsequent to the selection of the Boeing and Lockheed Martin designs, Boeing acquired McDonnell Douglas and
merged the two firms’ JSF teams.
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slightly improved version of the F-35A occurred on November 14, 2009.35 The F-35C first flew
on June 6, 2010.36
The F-35B’s ability to hover, scheduled for demonstration in November 2009, was shown for the
first time on March 17, 2010.37 The first vertical landing took place the next day.38
Summary of Program History
On December 21, 2016, then-President-elect Donald J. Trump received a background briefing on
the F-35 program, designed to summarize the program’s status and challenges. Although the
program has progressed since then, it may be interesting to see how DOD characterizes the
history of the program when it is not for a public audience. The pertinent chart presented to
President-elect Trump is shown in Figure 2. Details of the program history follow.

35 “First Flight,” Defense Daily, November 23, 2009, p. 3.
36 Graham Warwick, “JSF Carrier Variant Meets Handling Goals On First Flight,” Aerospace Daily, June 7, 2010.
37 Graham Warwick, “F-35B Hovers for First Time,” Aviation Week/Ares blog, March 17, 2010.
38 Graham Warwick, “STOVL F-35B Makes First Vertical Landing,” Aviation Week/Ares blog, March 18, 2010.
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Figure 2. F-35 Program History
(As briefed to President-Elect Trump, 2016)

Source: Joseph Trevithick, “These Are The Briefings President-Elect Trump Got On The F-35, Air Force One,
and Nukes,” The War Zone, April 19, 2019, https://www.thedrive.com/the-war-zone/27541/these-are-the-
briefings-president-elect-trump-got-on-the-f-35-air-force-one-and-nukes.
F-35B 3,000 lb. Overweight; Added Three Years/$6.5B
A significant issue in early development, noted in Figure 2, was the weight of the F-35B variant. Because the
F-35B takes off and lands near-vertically, weight is a particularly critical factor, as aircraft performance with low- to
no-airspeed depends directly on the ratio of engine thrust to aircraft weight.
The delay was exacerbated by the consolidation of the former JAST and ASTOVL programs, discussed in footnote
33. Normally, in a development program, the most technically simple variant is developed first, and lessons are
applied while working up to more complicated variants. Because the Marine Corps’ Harrier fleet was reaching the
end of life before the Air Force and Navy fleets the F-35 was designed to replace, in this case, the most
complicated variant—the F-35B—had to be developed first. That meant the technical challenges unique to STOVL
aircraft delayed all of the variants.
February 2010 Program Restructuring
In November 2009, DOD’s Joint Estimating Team issued a report (called JET II) stating that the
F-35 program would need an extra 30 months to complete the SDD phase. In response to JET II,
the then-impending Nunn-McCurdy breach, and other developments, on February 24, 2010,
Pentagon acquisition chief Ashton Carter issued an Acquisition Decision Memorandum (ADM)
restructuring the F-35 program. Key elements of the restructuring included the following:
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 Extending the SDD phase by 13 months, thus delaying Milestone C (full-rate
production) to November 2015 and adding an extra low-rate initial production
(LRIP) lot of aircraft to be purchased during the delay. Carter proposed to make
up the difference between JET II’s projected 30-month delay and his 13-month
schedule by adding three extra early-production aircraft to the test program. It is
not clear how extra aircraft could be added promptly if production was already
behind schedule.
 Funding the program to the “Revised JET II” (13-month delay) level, implicitly
accepting the JET II findings as valid.
 Withholding $614 million in award fees from the contractor for poor
performance, while adding incentives to produce more aircraft than planned
within the new budget.
 Moving procurement funds to R&D. “More than $2.8 billion that was budgeted
earlier to buy the military’s next-generation fighter would instead be used to
continue its development.”39
“Taken together, these forecasts result in the delivery of 122 fewer aircraft over the Future Years
Defense Program (FYDP), relative to the President’s FY 2010 budget baseline,” Carter said.40
This reduction led the Navy and Air Force to revise their dates for IOC as noted above.
March 2010 Nunn-McCurdy Breach
On March 20, 2010, DOD formally announced that the JSF program had exceeded the cost
increase limits specified in the Nunn-McCurdy cost containment law, as average procurement
unit cost, in FY2002 dollars, had grown 57% to 89% over the original program baseline. Simply
put, this requires the Secretary of Defense to notify Congress of the breach, present a plan to
correct the program, and to certify that the program is essential to national security before it can
continue.41
On June 2, 2010, the Under Secretary of Defense for Acquisition, Technology and
Logistics issued an Acquisition Decision Memorandum (ADM) certifying the F-35
Program in accordance with section 2433a of title 10, United States Code. As required by
section 2433a, of title 10, Milestone B was rescinded. A Defense Acquisition Board (DAB)
was held in November 2010.... No decision was rendered at the November 2010 DAB....
Currently, cumulative cost and schedule pressures result in a critical Nunn-McCurdy
breach to both the original (2001) and current (2007) baseline for both the Program
Acquisition Unit Cost (PAUC) and Average Procurement Unit Cost (APUC). The breach
is currently reported at 78.23% for the PAUC and 80.66% for the APUC against the
original baseline and 27.34% for the PAUC and 31.23% for the APUC against the current
baseline.42

39 Tony Capaccio, “Lockheed F-35 Purchases Delayed in Pentagon’s Fiscal 2011 Plan,” Bloomberg News, January 6,
2010.
40 F-35 Lightning II Joint Strike Fighter (JSF) Program Restructure Acquisition Decision Memorandum (ADM), Under
Secretary of Defense (Acquisition, Technology & Logistics), February 24, 2010.
41 For a history of the Nunn-McCurdy law and options for its future, see CRS Report R41293, The Nunn-McCurdy Act:
Background, Analysis, and Issues for Congress, by Heidi M. Peters and Charles V. O'Connor.
42 Office of the Secretary of Defense, Selected Acquisition Report (SAR): F-35, December 31, 2010, p. 4.
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February 2012 Procurement Stretch
With the FY2013 budget, F-35 acquisition was slowed, with the acquisition of 179 previously
planned aircraft being moved to years beyond the FY2013-2017 FYDP “for a total of $15.1
billion in savings.”43 Note that this stretch, along with the SDD extension already mentioned,
contributed to the “6.5 years late” referenced in Figure 2.
COVID-19-Related Production Slowdown
On May 19, 2020, Lockheed Martin officials announced a restructuring of the F-35 production
plan to account for slowdowns in parts deliveries resulting from the impact of the COVID-19
pandemic on subcontractor production rates. The plan was designed to minimize workforce
impacts at the principal F-35 production line in Fort Worth, TX. The restructuring and other
COVID-19 effects were expected to reduce the 141 F-35 deliveries planned in 2020 to between
117 and 123. Lockheed had previously changed production methods and cleaning protocols in
response to possible COVID-19 cases in its assembly line workforce.44
Initial Operational Capability
Congress required a formal declaration of IOCs in Section 155 of the National Defense
Authorization Act for Fiscal Year 2013 (P.L. 112-239). The current dates (by fiscal year) are
shown in Table 1.
The F-35A, F-35B, and F-35C were originally scheduled to achieve IOC in March 2013, March
2012, and March 2015, respectively.45 The Marine Corps declared F-35B Initial Operational
Capability (IOC) on July 31, 2015. The Air Force declared F-35A IOC on August 2, 2016.46 The
Navy declared IOC on February 28, 2019.47
It should be noted that IOC means different things to different services:
F-35A initial operational capability (IOC) shall be declared when the first operational
squadron is equipped with 12-24 aircraft, and Airmen are trained, manned, and equipped
to conduct basic Close Air Support (CAS), Interdiction, and limited Suppression and
Destruction of Enemy Air Defense (SEAD/DEAD) operations in a contested environment.
Based on the current F-35 Joint Program Office (JPO) schedule, the F-35A will reach the
IOC milestone between August 2016 (Objective) and December 2016 (Threshold)....

43 Tony Capaccio, “Pentagon Takes $1.6 Billion From Lockheed F-35 in Biggest Cut,” Bloomberg News, February 13,
2012.
44 See, inter alia, Anthony Capaccio, “Lockheed Slowing F-35 Production Amid Covid-Related Parts Delays,”
Bloomberg News, May 19, 2020, https://www.bloomberg.com/news/articles/2020-05-19/lockheed-slowing-f-35-
production-amid-covid-related-parts-delays, and Valerie Insinna, “Lockheed slated to miss F-35 delivery target in 2020
as supply chain struggles to keep up,” Defense News, May 19, 2020, https://www.defensenews.com/breaking-news/
2020/05/19/lockheed-to-slow-f-35-production-as-supply-chain-struggles-to-keep-up/.
45 The Navy had initially accelerated its estimated IOC for the F-35C to September 2014. Andrew Tilghman, “Joint
Strike Fighter Timeline Moved Up,” NavyTimes.com, September 18, 2009. In November 2009, Lockheed announced
that the first flight of an F-35C test aircraft would be delayed from the final quarter of 2009 to the first quarter of 2010.
(Dan Taylor, “Navy Joint Strike Fighter Carrier Variant Test Aircraft Will Not Fly Until 2010,” Inside the Navy,
November 9, 2009.)
46 “Air Force Declares F-35A Lightning II ‘Combat Ready,’” Air Force News Service, August 3, 2016,
https://go.usa.gov/xQbTg.
47 Commander Naval Air Forces Public Affairs, F-35C Achieves Initial Operational Capability, Story Number:
NNS190228-18, San Diego, CA, February 28, 2019, https://www.navy.mil/submit/display.asp?story_id=108746.
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F-35B IOC shall be declared when the first operational squadron is equipped with 10-16
aircraft, and US Marines are trained, manned, and equipped to conduct CAS, Offensive
and Defensive Counter Air, Air Interdiction, Assault Support Escort, and Armed
Reconnaissance in concert with Marine Air Ground Task Force resources and capabilities.
Based on the current F-35 JPO schedule, the F-35B will reach the IOC milestone between
July 2015 (Objective) and December 2015 (Threshold)....
Navy F-35C IOC shall be declared when the first operational squadron is equipped with 10
aircraft, and Navy personnel are trained, manned and equipped to conduct assigned
missions. Based on the current F-35 JPO schedule, the F-35C will reach the IOC milestone
between August 2018 (Objective) and February 2019 (Threshold).48
Additionally,
Each of the three US services will reach initial operating capability (IOC) with different
software packages.
The F-35B will go operational for the US Marines in December 2015 with the Block 2B
software, while the Air Force plans on achieving IOC on the F-35A in December 2016
with Block 3I, which is essentially the same software on more powerful hardware. The
Navy intends to go operational with the F-35C in February 2019, on the Block 3F
software.49
One complication regarding the Navy’s operational capability is that the Navy reportedly will not
be able to airlift F-35 engines to carriers at sea until the introduction of the CMV-22 carrier
onboard delivery aircraft in 2021.50
End of System Development and Demonstration/Entry into IOT&E
The F-35 Joint Program Office declared the 17-year System Development and Demonstration
(SDD) effort complete on April 11, 2018. “(T)he developmental flight team has conducted more
than 9,200 sorties, accumulated 17,000 flight hours and executed more than 65,000 test points.”51
The end of the flight test effort does not mark the actual end of SDD, though; that will occur at
Milestone C, following the completion of initial operational test and evaluation (IOT&E).
The Director of Operational Test and Evaluation (DOT&E) approved entering formal IOT&E on
December 3, 2018. DOT&E notes that the F-35 enters IOT&E with 873 unresolved deficiencies,
13 of which are classified as “Category 1 ‘must-fix’ items that affect safety or combat
capability.”52 The program’s high concurrency means there may be substantial costs to
incorporate the lessons of testing: “IOT&E, which provides the most credible means to predict
combat performance, likely will not be completed until … over 600 aircraft will already have
been built.”53

48 U.S. Navy, United States Marine Corps, United States Air Force, F-35 Initial Operational Capability, June 2013.
49 Aaron Mehta, “After ‘Transformative’ Year, F-35 Program Focuses on Software, Quantity,” Defense News, January
14, 2014.
50 Mark D. Faram, “CMV-22 Osprey will deploy on Vinson with F-35C in 2021,” Navy Times, April 10, 2018,
https://www.navytimes.com/news/your-navy/2018/04/09/cmv-22-osprey-will-deploy-on-vinson-with-f-35c-in-2021/.
51 Lara Seligman, “F-35 Completes Flight Trials, Now On To Final Test,” Aerospace Daily and Defense Report, April
12, 2018, http://aviationweek.com/defense/f-35-completes-flight-trials-now-final-test.
52 Anthony Capaccio, “F-35’s Gun That Can’t Shoot Straight Adds to Its Roster of Flaws,” Bloomberg News, January
30, 2020, https://www.instapaper.com/read/1273117282.
53 Director, Operational Test & Evaluation, FY 2017 Annual Report, January 2018, p. 39.
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Procurement Quantities
Planned Total Quantities
The F-35 program includes a planned total of 2,470 aircraft for the Air Force, Marine Corps, and
Navy. This comprises 14 research and development aircraft and 2,456 production aircraft: 1,763
F-35As for the Air Force, 273 F-35Cs for the Navy, and 67 F-35Cs and 353 F-35Bs for the
Marine Corps.54 As noted in “Potential Change in Marine Corps Procurement” above, the Marine
Corps recently mooted a change in squadron size that would imply a 54-jet reduction in its
planned F-35 fleet, but that has not yet become a validated goal.
Annual Quantities
DOD began procuring F-35s in FY2007. Figure 3 shows F-35 procurement quantities authorized
through FY2020, requested procurement quantities for FY2021, and projected requests through
the FYDP. The figures in the table do not include 14 research and development aircraft procured
with research and development funding. (Quantities for foreign buyers are discussed in the next
section.)
Figure 3. F-35 Procurement Quantities
(Figures shown are for production aircraft; table excludes 14 research and development aircraft)

Source: Prepared by CRS based on DOD data.

54 “IHS Jane’s Defence Insight Report: Air Platforms,” June 2013. In 1996, preliminary planning estimated over 3,000
F-35s for DOD and the UK: 2,036 for the Air Force, 642 for the Marines, 300 for the U.S. Navy, and 60 for the Royal
Navy. In May 1997, the QDR recommended reducing projected DOD procurement from 2,978 to 2,852: 1,763 for the
Air Force, 609 for the Marines, and 480 for the Navy. (Quadrennial Defense Review Cuts Procurement in FY1999,
2000, Aerospace Daily, May 20, 1997, p. 280.) In 2003, the Navy reduced its planned procurement of 1,089 F-35Bs
and Cs to 680 aircraft as part of the Navy/Marine Corps Tactical Aviation Integration Plan; that requirement was
revised in 2016 to 693. See CRS Report RS21488, Navy-Marine Corps Tactical Air Integration Plan: Background and
Issues for Congress, by Christopher Bolkcom and Ronald O'Rourke (out of print; available to congressional clients
from the author upon request). See also DOD, Selected Acquisition Report: F-35 Lightning II Joint Strike Fighter (JSF)
Program (F-35), March 19, 2018.
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Previous DOD plans contemplated increasing the procurement rate of F-35As for the Air Force to
a sustained rate of 80 aircraft per year by FY2015, and completing the planned procurement of
1,763 F-35As by about FY2034. The current Air Force plan levels procurement at 48 per year
beginning in 2020; the 1,763 fleet target has not changed.
Past DOD plans also contemplated increasing the procurement rate of F-35Bs and Cs for the
Marine Corps and Navy to a combined sustained rate of 50 aircraft per year by about FY2014,
and completing the planned procurement of 680 F-35Bs and Cs by about FY2025. The FY2021
budget submission shows a combined F-35B and -C production rate of 30 per year in 2021,
toward a fleet goal of 693.
Potential Change in Marine Corps Procurement
On March 23, 2020, the Marine Corps released a “New Force Design Initiative” outlining
proposed changes to its force structure. The proposal included reducing the primary aircraft
authorization (PAA) of Marine F-35 squadrons from 16 to 10 each. This would affect nine F-35B
squadrons (five other active and two reserve F-35B squadrons were already planned to be at 10
PAA). The Corps also has four F-35C squadrons, but those had also previously been planned for
10 PAA.55 The Marine proposal would appear to require 54 fewer F-35Bs than in the existing
program of record, currently 353 F-35Bs and 67 F-35Cs.56 The Air Force has also been
considering force mix changes that could affect the number of F-35s acquired (see the “Issues for
Congress” section below).
Proposed Multiyear Procurement
In the December 2017 Selected Acquisition Report, DOD disclosed an intention to acquire F-35s
through multiyear contracting.
From FY 2021 to the end of the program, the USAF production profile assumes one 3-year
multi-year procurement (FY 2021-FY 2023) followed by successive 5-year multi-year
procurements beginning in FY2024, with the required EOQ investments and associated
savings. The Department of Navy (DoN) did not include EOQ funding in the PB 2019
submission for a multiyear in FY 2021-2023 for either the F-35B or F-35C. The DoN plans
to reassess that decision in the coming FY 2020 budget cycle. Therefore, the DoN PB 2019
production profile assumes annual procurements from FY 2021-2023, followed by
successive 5-year multi-year procurements from FY 2024 to the end of the program with
necessary EOQ investments and associated savings.57
Subsequent hearings considered the merits of multiyear contracting, but Congress has yet to grant
that authority. The FY2020 National Defense Authorization Act (P.L. 116-92) authorized
economic order quantity contracting and buy-to-budget acquisition, a variation on multiyear
contracting. 58 For a discussion of the differences, see the “F-35 Block Buy” section below.

55 U.S. Marine Corps, 2019 Marine Corps Aviation Plan, Washington, DC, 2019, p. 36,
https://www.aviation.marines.mil/portals/11/2019%20avplan.pdf.
56 U.S. Marine Corps, Force Design 2030, March 2020, p. 7, https://go.usa.gov/xvqF9.
57 Office of the Secretary of Defense, Selected Acquisition Report (SAR): F-35 Joint Strike Fighter Aircraft (F-35),
March 19, 2018, p. 11.
58 See, inter alia, Christen McCurdy, “Congress, Pentagon to hold off on multiyear F-35 contract,” UPI, November 14,
2019, https://www.upi.com/Defense-News/2019/11/14/Congress-Pentagon-to-hold-off-on-multiyear-F-35-contract/
2731573693286/.
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Low-Rate Initial Production
F-35s are currently produced under Low-Rate Initial Production (LRIP), with agreements reached
for the first 14 lots of aircraft. Each LRIP lot includes both U.S. and international partner aircraft.
Contracted unit prices for F-35s have continued to decline with each production lot. “For
example, the price (including airframe, engine and profit) of an LRIP Lot 8 aircraft was
approximately 3.6 percent less than an LRIP Lot 7 aircraft, and an LRIP Lot 7 aircraft, was 4.2
percent lower than an LRIP Lot 6 aircraft.”59
In LRIPs 5, 6, and 7, any cost overruns associated with concurrent development and production
would be split equally between the contractor and the government. Prior to LRIP 4, the
government bore those costs alone. Beginning with LRIP 8, the contractor is liable for 100% of
any cost overrun; if actual cost is lower than the contracted cost, the contractor will receive 80%
of the savings, the government 20%.60
Table 2. F-35 LRIPs 5-11
(Quantity/Cost in millions of dollars, per aircraft)
LRIP Lot
5a
6b
7c, d
8e
9f
10g
11h
F-35A
22/105
23/103
19/98
19/95
42/102
44/95
102/89
F-35B
3/113
7/109
6/104
6/102
13/132
9/123
25/116
F-35C
7/125
6/120
4/116
4/116
2/132
2/122
14/108
Notes: Aircraft costs for LRIPs 5-8 shown do not include engines. All quantities exclude international orders.
a. Christopher Drew, “Lockheed Profit on F-35 Jets Wil Rise With New Contract,” The New York Times,
December 17, 2012.
b. Tony Capaccio, “Lockheed Gets Approval Of Next F-35 Production Contract,” Bloomberg News, July 6,
2012.
c. Amy Butler, “Latest F-35 Deal Targets Unit Cost Below $100 Mil ion,” Aviation Week & Space Technology,
July 30, 2013.
d. Caitlin Lee, “Latest F-35 contracts mark new strategy to reduce costs,” Jane’s Defence Weekly, September
29, 2013.
e. Colin Clark, “New F-35 Prices: A: $95M; B: $102M; C: $116M,” Breaking Defense, November 21, 2014.
f.
Sydney J. Freedberg, Jr., “F-35 ‘Not Out Of Control’: F-35A Prices Drop 5.5%,” Breaking Defense, December
19, 2016, https://breakingdefense.com/2016/12/33483/.
g. Lockheed Martin, “Agreement Reached on Lowest Priced F-35s in Program History,” press release,
February 3, 2017, https://www.f35.com/news/detail/agreement-reached-on-lowest-priced-f-35s-in-program-
history.
h. Lockheed Martin, Producing, Operating and Supporting a 5th Generation Fighter, retrieved March 29, 2020,
https://www.f35.com/about/cost.
Although previous LRIP contracts had been arrived at through negotiation between the F-35 Joint
Program Office and Lockheed Martin, the LRIP 9 contract was not agreed to by both sides. After
prolonged negotiation, the government invoked its right to issue a unilateral contract.61

59 Office of the Secretary of Defense, Selected Acquisition Report (SAR): F-35 Joint Strike Fighter Aircraft (F-35),
March 21, 2016, p. 9.
60 Colin Clark, “New F-35 Prices: A: $95M; B: $102M; C: $116M,” Breaking Defense, November 21, 2014.
61 See, inter alia, Colin Clark, “F-35: DoD Forces Lockheed To Accept Its Price For LRIP 9,” Breaking Defense,
November 2, 2016, https://breakingdefense.com/2016/11/jpo-to-lockheed-no-more-talkie-heres-lrip-9-deal/.
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F-35 Block Buy
The LRIP 11 award, incorporating as it does options for lots 12-14, has been labeled a block
buy.62 Block buy contracts commit the government to purchasing certain quantities of aircraft
over a number of years, which allows the contractor to acquire parts in greater quantity and plan
workforce levels in advance, helping to reduce cost. “By purchasing supplies in economic
quantities, Lockheed Martin and Pratt & Whitney estimate that 8 percent and 2.3 percent cost
savings, respectively, could be achievable.”63 A 2018 RAND Corporation analysis offered some
of the possible savings from a (then-mooted) block buy.64
What Is Block Buy?65
Block buy contracting (BBC) permits DOD to use a single contract for more than one year’s worth of
procurement of a given kind of item without having to exercise a contract option for each year after the first year.
It is similar to multiyear procurement in that DOD needs congressional approval for each use of BBC.
BBC differs from MYP in the fol owing ways:

There is no permanent statute governing the use of BBC.

There is no requirement that BBC be approved in both a DOD appropriations act and an act other than a
DOD appropriations act.

Programs being considered for BBC do not need to meet any legal criteria to qualify for BBC because there
is no permanent statute governing the use of BBC that establishes such criteria.

A BBC contract can cover more than five years of planned procurements. The BBC contracts currently being
used by the Navy for procuring Littoral Combat Ships, for example, cover a period of seven years (FY2010-
FY2016).

Economic order quantity (EOQ) authority does not come automatically as part of BBC authority because
there is no permanent statute governing the use of BBC that includes EOQ authority as an automatic feature.
To provide EOQ authority as part of a BBC contract, the provision granting authority for using BBC in a
program may need to state explicitly that the authority to use BBC includes the authority to use EOQ.

BBC contracts are less likely to include cancellation penalties.
“A full block buy, including US jets, could save anywhere from $2 billion to $2.8 billion,
according to industry estimates.”66 Congressional approval would be required for a U.S. block
buy.67
In related developments, Section 141 of the Fiscal Year 2018 National Defense Authorization Act
included language authorizing DOD to enter into economic order quantity contracts for advance

62 Gareth Jennings, “US DoD awards first block-buy for F-35,” Jane’s Defence Weekly, October 30, 2019,
https://www.janes.com/article/92238/us-dod-awards-first-block-buy-for-f-35.
63 U.S. Government Accountability Office, F-35 JOINT STRIKE FIGHTER: Continued Oversight Needed as Program
Plans to Begin Development of New Capabilities, 16-390, April 2016, p. 23, http://www.gao.gov/assets/680/
676584.pdf.
64 James D. Powers et al., F-35 Block Buy: An Assessment of Potential Savings, RAND Project Air Force, RR2063,
Santa Monica, CA, 2018, https://www.rand.org/content/dam/rand/pubs/research_reports/RR2000/RR2063/
RAND_RR2063.pdf.
65 Description adapted from CRS Testimony TE10004, The Status of Coast Guard Cutter Acquisition Programs, by
Ronald O'Rourke.
66 Valerie Insinna, “Program Head Hints F-35 Contract Could Be Announced at Farnborough,” Defense News, July 9,
2016.
67 For a more detailed discussion of block buy, see CRS Report R41909, Multiyear Procurement (MYP) and Block Buy
Contracting in Defense Acquisition: Background and Issues for Congress, by Ronald O'Rourke.
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parts for F-35s to be procured in FY2019 and FY2020, and the FY2020 NDAA (P.L. 116-92)
authorized economic order quantity and buy-to-budget for F-35 aircraft.
Lots 12-14 Agreed To
On June 10, 2019, DOD and Lockheed Martin reached initial agreement on F-35 production Lot
12, with options for Lots 13 and 14. The deal would encompass 478 aircraft for $34 billion,
including sales to international partners. 68 On October 29, 2019, negotiations were concluded
with 149, 160, and 169 aircraft in the respective lots.69 While the contract announcement provided
no breakdown of those numbers by model and year, it did specify that 106 were for the United
States (64 F-35As, 26 F-35Bs, and 16 F-35Cs) with 71 F-35As and 18 F-35Bs for foreign
countries participating in the consortium and 60 F-35As for Foreign Military Sales customers.70
As noted in the “Lots 15-17 Under Negotiation” section above, prices have not been concluded
for the last three lots shown in Table 3.
Table 3. F-35 LRIPs 12-17
(Quantity/Cost in millions of dollars, per aircraft)
LRIP Lot
12
13
14
15
16
17
F-35A
??/82
??/79
??/78
116/??
101/??
98/??
F-35B
??/108
??/105
??/101
29/??
32/??
37/??
F-35C
??/103
??/98
??/94
24/??
24/??
24/??
Source: LRIP 12-14 costs from Lockheed Martin, “F-35 LRIP 12-14 Fact Sheet,” press release, October 29,
2019, https://www.f35.com/content/dam/lockheed-martin/aero/f35/documents/f-35_lot_12-14factsheet_-
_29_oct_2019.pdf. Projected LRIP 15-17 quantities from Department of Defense, LOTs 15-17 Pre Solicitation
Notice, February 13, 2019, https://go.usa.gov/xtj99.
Notes: LRIP 15-17 prices not yet agreed on. In the undefinitized contract action for LRIP 12-14, quantities per
model per year are not disclosed.
Program Management
The JSF joint program office is jointly managed and staffed by the Department of the Air Force
and the Department of the Navy. Service Acquisition Executive (SAE) responsibility alternates
between the two departments. When the Air Force has SAE authority, the F-35 program director
is from the Navy, and vice versa. Air Force Lt Gen Eric T. Fick became the F-35 program
manager, succeeding Navy Vice Admiral Mathias Winter, on July 11, 2019.71
Recognizing that the bulk of F-35 development has been completed, and consonant with broader
congressional direction to decentralize acquisition and increase the acquisition authority of the

68 Lockheed Martin, “Pentagon and Lockheed Martin Reach Handshake Agreement on F-35 Production Contract,”
press release, June 10, 2019, https://www.f35.com/news/detail/pentagon-and-lockheed-martin-reach-handshake-
agreement-on-f-35-product1.
69 C. Todd Lopez, DOD Finalizes Purchase Plan for F-35 Aircraft, Department of Defense, Washington, DC, October
29, 2019, https://www.defense.gov/Explore/News/Article/Article/2002585/dod-finalizes-purchase-plan-for-f-35-
aircraft/.
70 Department of Defense, Contracts for Nov. 14, 2018, November 14, 2018, https://go.usa.gov/xtj5e.
71 U.S. Navy, “F-35 Program Sees Changing of Guard,” press release, July 12, 2019, https://www.navy.mil/submit/
display.asp?story_id=110201.
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military services,72 Congress ordered that the joint program office’s sustainment and acquisition
functions be transferred to the Navy and Air Force in the National Defense Authorization Act for
Fiscal Year 2022 (P.L. 117-81).
Congress earlier required DOD to examine alternative F-35 management structures.73 Proponents
of transfer argued that the overhead structure of a joint office, even if useful in overseeing
development of a joint aircraft, is not needed once production has been established. Further, they
argued that the F-35 is functionally three separate aircraft, with much less commonality than
envisioned early in the program. “[E]ven the Program Executive Officer of the F-35 Joint
Program Office, General Christopher Bogdan, recently admitted the variants are only 20–25
percent common.”74 Supporters cited the requirement by the United States to support international
customers and to oversee further software and other upgrades as reasons to keep the office in
place.75
In a letter to Congress accompanying that report, Under Secretary of Defense for Acquisition and
Sustainment Ellen Lord declared an intention to
begin a deliberate, conditions-based, and risk-informed transition ... from the existing F-35
management structure to an eventual management structure with separate Service-run F-
35A and F-35B/C program offices that are integrated with and report through the individual
Military Departments.76
Software Development
You can see from its angled lines, the F-35 is a stealth aircraft designed to evade enemy
radars. What you can't see is the 24 million lines of software code which turn it into a flying
computer. That’s what makes this plane such a big deal.77
The F-35’s integration of sensors and weapons, both internally and with other aircraft, is touted as
its most distinctive aspect. As that integration is primarily realized through complex software, it
may not be surprising to observe that writing, validating, and debugging that software is among
the program’s greatest challenges. F-35 operating software is released in blocks, with additional
capabilities added from one block to the next.
I’m concerned about the software, the operational software.... And I’m concerned about
the ALIS [Autonomic Logistics Information System], that is another software system,

72 CRS Report R45068, Acquisition Reform in the FY2016-FY2018 National Defense Authorization Acts (NDAAs), by
Heidi M. Peters.
73 Section 146 of the FY2017 National Defense Authorization Act (P.L. 114-328).
74 S.Rept. 114-255, p. 280.
75 See, inter alia, Oriana Pawlyk, “As Services Take Greater Role on F-35, Joint Program Office to Remain,”
Military.com, April 11, 2018, https://www.military.com/dodbuzz/2018/04/11/services-take-greater-role-f-35-joint-
program-office-remain.html; Valerie Insinna, “F-35 program head supportive of future transition to service-led
offices,” Defense News, April 12, 2018, https://www.defensenews.com/digital-show-dailies/navy-league/2018/04/11/f-
35-program-head-supportive-of-future-transition-to-service-led-offices/; and Marc Selinger, “DoD Eyes Shifting F-35
Management To Military Services,” Defense Daily, April 4, 2018.
76 Letter from Ellen M. Lord, Under Secretary (Acquisition and Sustainment), to Rep. Mac Thornberry, Chairman,
House Committee on Armed Services, March 27, 2018.
77 David Martin, “Is the F-35 worth it?,” 60 Minutes, February 16, 2014.
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basically that will provide the logistics support to the systems. – Frank Kendall, Under
Secretary of Defense for Acquisition, Technology & Logistics.78
Currently, the ultimate planned software release is Block 4, which will be the first block to
contain full combat capability and a complete weapons suite, including conventional weapons
like the Small Diameter Bomb II and nuclear capability. However, Block 4 will not be available
to all F-35s; it will require aircraft upgraded with Technical Refresh-3 (TR-3) hardware.79 New F-
35s are expected to begin delivering with TR-3 in lot 15, scheduled for CY2023.80
Table 4. F-35 Software Block Schedule
Block
Attributes
Released
2B
Required for Marine IOC
March, 2015
3i (initial)
Required for USAF IOC; basic
August, 2016
aircraft operation and navigation,
some combat capability.
3F (final) (now called 30PXX)
Required for Navy IOC; expanded
September, 2017
combat capability with basic
weapons.
4
Adds nuclear weapons capability
Under development
(among other things)
Source: Compiled by CRS from various sources.
Kendall’s concern was echoed by then-F-35 program manager Air Force Lieutenant General
Christopher Bogdan. In testimony to the House Armed Services Subcommittee on Tactical Air
and Land Forces, he noted that it is the
“complexity of the software that worries us the most.... Software development is always
really, really tricky... We are going to try and do things in the final block of this capability
that are really hard to do.” Among them is forming software that can share the same threat
picture among multiple ships across the battlefield, allowing for more coordinated
attacks.81
C2D2 Program
Beginning in 2018, upgrades to the F-35’s software and other capabilities were combined in an
effort now known as Continuous Capability Development and Delivery (C2D2). C2D2’s
principal task is developing the Block 4 software, but it includes other elements like TR-3 and
dual (nuclear) capability, discussed below. According to the Director of Operational Test and
Evaluation,
The current Continuous Capability Development and Delivery (C2D2) process has not
been able to keep pace with adding new increments of capability as planned. Software

78 Aaron Mehta, “After ‘Transformative’ Year, F-35 Program Focuses on Software, Quantity,” Defense News, January
14, 2014. Kendall is now Secretary of the Air Force.
79 Valerie Insinna, “F-35 upgrade plan awaiting approval from top Pentagon acquisition exec,” Defense News, October
2, 2018, https://www.defensenews.com/air/2018/10/02/f-35-upgrade-plan-awaiting-approval-from-top-pentagon-
acquisition-exec/.
80 Director, Operational Test and Evaluation, FY2019 Annual Report, December 20, 2019, p. 21.
81 Amy Butler, “Bogdan Warns Of Possible Six-Month F-35 Slip After Development Ends,” AviationWeek.com,
February 26, 2014.
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changes, intended to introduce new capabilities or fix deficiencies, often introduced
stability problems and adversely affected other functionality. 82
According to the Government Accountability Office, that development is now behind schedule
and over budget:
Since May 2019, we found the program office has increased its estimate by about 14
percent, to $12.1 billion, primarily due to schedule delays. The program now expects to
extend the delivery of Block 4 capabilities by 2 additional years, through 2026…
Additionally, most of the capabilities the F-35 program planned to deliver in 2019 were
delayed.83
C2D2 Program Oversight
A shown in Table 5, the FY2021 budget submission projects the cost of C2D2 as $7.0 billion to
FY2025. International partners may contribute to this development effort; according to then-F-35
program executive officer Vice Admiral Mathias Winter in 2018, consortium partners were
prepared to contribute $3.7 billion toward Block 4 software development through 2024.84 Some in
Congress argue that a program of that size should part with traditional procurement practice for
an upgrade and be run as a separate Major Defense Acquisition Program, with its own budget line
and the concomitant reporting requirements; language to this effect was included in the Senate’s
version of the FY2017 National Defense Authorization Act. This is discussed further in “Issues
for Congress,” below.
Table 5. C2D2 Budgets, FY2021-FY2025
(In millions of dollars)
FY21
FY22
FY23
FY24
FY25
Total

F-35A
785.336
549.279
450.915
521.012
586.709
2893.251

F-35B
379.549
323.597
294.404
283.981
244.932
1526.463

F-35C
330.386
261.923
246.494
265.615
248.487
1352.905

International 359.626
285.969
211.292
208.053
177.542
1242.482
All

7015.101

Source: FY2021 DOD RDT&E budget submission books for Air Force and Navy. The FY2022 budget books did
not include outyear projections.
Notes: Only line items specifically designated as C2D2.
The $7.0 billion specifically designated for C2D2 may not be the total funding for the program, as
Vice Admiral Winter had earlier indicated that just the cost for the Block 4 upgrade was to be
more than $10 billion through FY2024.85

82 Director, Operational Test and Evaluation, FY2019 Annual Report, December 20, 2019, p. 19.
83 U.S. Government Accountability Office, F-35 JOINT STRIKE FIGHTER: Actions Needed to Address Manufacturing
and Modernization Risks, GAO-20-339, May, 2020, p. 31, https://www.gao.gov/products/GAO-20-339.
84 Pat Host, “Pentagon faces major cost increase on F-35 Block 4 modernisation,” IHS Jane’s Defence Weekly, March
8, 2018, http://www.janes.com/article/78443/pentagon-faces-major-cost-increase-on-f-35-block-4-modernisation.
85 Pat Host, “Pentagon faces major cost increase on F-35 Block 4 modernisation,” IHS Jane’s Defence Weekly, March
8, 2018, http://www.janes.com/article/78443/pentagon-faces-major-cost-increase-on-f-35-block-4-modernisation.
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Autonomic Logistics Information System
The issues cited above focused on software development for the F-35’s onboard mission systems.
A supporting system, the Autonomic Logistics Information System (ALIS), also requires
extensive software development and testing. “ALIS is at the core of operations, maintenance and
supply-chain management for the F-35, providing a constant stream of data from the plane to
supporting staff.”86 The pace of ALIS development has been cited by service officials as
hindering F-35 deployment.
DOD’s Director of Operational Test & Evaluation stated that
Although the program released several new versions of ALIS in 2019 that improved ALIS
usability, these improvements did not eliminate the major problems in ALIS design and
implementation. These deficiencies caused delays in troubleshooting and returning broken
aircraft to mission capable status.87
GAO reported that
ALIS may not be deployable: ALIS requires server connectivity and the necessary
infrastructure to provide power to the system. The Marine Corps, which often deploys to
austere locations, declared in July 2015 its ability to operate and deploy the F-35 without
conducting deployability tests of ALIS. A newer version of ALIS was put into operation
in the summer of 2015, but DOD has not yet completed comprehensive deployability tests.
ALIS does not have redundant infrastructure: ALIS’s current design results in all F-35 data
produced across the U.S. fleet to be routed to a Central Point of Entry and then to ALIS’s
main operating unit with no backup system or redundancy. If either of these fail, it could
take the entire F-35 fleet offline.88
To date, the F-35’s operators have been coping with ALIS’s shortcomings. “Most capabilities
function as intended only with a high level of manual effort by ALIS administrators and
maintenance personnel. Manual work-arounds are often needed to complete tasks designed to be
automated.”89
Air Force Lt. Gen. Chris Bogdan told reporters that the plane could fly without the $16.7
billion ... ALIS for at least 30 days. The software, which runs on ground computers, not
the plane itself, manages the aircraft’s supply chain, aircraft configuration, fault
diagnostics, mission planning, and debriefing – none of which are critical to combat
flight.90

86 Aaron Mehta, “After ‘Transformative’ Year, F-35 Program Focuses on Software, Quantity,” Defense News, January
14, 2014.
87 Director, Operational Test and Evaluation, FY2019 Annual Report, December 20, 2019, p. 20.
88 U.S. Government Accountability Office, F-35 Sustainment: DOD Needs a Plan to Address Risks Related to Its
Central Logistics System, 16-439, April 14, 2016.
89 Director, Operational Test and Evaluation, FY2017 Annual Report, January 2018, p. 53.
90 Patrick Tucker, “F-35 Will Fly Despite Auditor’s Fleet-Grounding Warning,” Defense One, April 17, 2016.
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ALIS Replacement
Some of the problems with ALIS reportedly stem from its 1990s-based architecture.91 DOD is
replacing ALIS with a new technology system called ODIN, for Operational Data Integrated
Network.92
ODIN is designed to be more user-friendly and less prone to error. Program officials decided to
replace ALIS rather than upgrading it further in order to take advantage of modern programming
architectures.
We have old hardware, we have old operating systems… if we were ever going to get to a
modern software architecture, modernizing ALIS wasn’t going to get us there.
[Replacement is] so that we can leverage all the things that have happened in software
development over the last couple of decades.
The code in this airplane is old… it’s frankly going to take a couple of years for this to all
iron itself out.93
ODIN will work with F-35s that have the Technical Refresh-3 hardware package, beginning with
acquisition Lot 15 in 2023. That package includes a new integrated core processor, panoramic
cockpit display, and an enhanced memory unit. The company intends to incorporate TR3 in F-35s
starting in Lot 15, with those jets rolling off the production lot in 2023.94 Earlier F-35s will, at
least initially, continue with ALIS version 3.5, which is being refreshed “roughly every 120 days
or so.” “ALIS 3.5 is going to be the core … capability for our sustainers until we get ODIN up
and online.”95
Dual Capability
Some F-35As will be dual capable aircraft (DCA), meaning that they will have the ability to
deliver nuclear ordnance. Dual capability is expected to be included in the Block 4 software
release, with initial capability for the B61-12 weapon.96 The F-35A DCA is scheduled to achieve
nuclear certification in January, 2023.97
Funding for DCA development has been carried alternately in Air Force PE 0207142F, under F-
35 Squadrons, and C2D2, PE 0604840F. Requested funding in FY2022, in PE 0207142F, is
$44.816 million; the FY2022 NDAA approved this sum.

91 Lara Seligman, “F-35 Sustainment Challenges Mount As Global Fleet Grows,” Aviation Week and Space
Technology, April 5, 2018, http://aviationweek.com/defense/f-35-sustainment-challenges-mount-global-fleet-grows.
92 See, inter alia, John A. Tirpak, “F-35 Program Dumps ALIS for ODIN,” Air Force, January 21, 2020,
https://www.airforcemag.com/f-35-program-dumps-alis-for-odin/.
93 Brigadier General David Abba, Director of the F-35 Integration Office, Headquarters U.S. Air Force, “Briefing to the
Mitchell Institute,” Arlington, VA, March 9, 2020, https://www.youtube.com/watch?v=DPvKWp7tSqY.
94 Valerie Insinna, “Lockheed hypes F-35’s upgrade plan as interest in ‘sixth-gen’ fighters grows,” Defense News, June
21, 2019, https://www.defensenews.com/digital-show-dailies/paris-air-show/2019/06/21/lockheed-hypes-f-35s-
upgrade-plan-as-interest-in-sixth-gen-fighters-grows/.
95 Brigadier General David Abba, op.cit.
96 Testimony of Lt Gen Christopher C. Bogdan, F-35 Program Executive Officer, before the U.S. Congress, House
Committee on Armed Services, Subcommittee on Tactical Air and Land Forces, Military Services Fifth–Generation
Tactical Aircraft Challenges and F–35 Joint Strike Fighter Program Update, 115th Cong., 1st sess., February 16, 2017,
H.A.S.C. No. 115–6 (Washington: GPO, 2017), p. 17. For more on the B61, see CRS Report RL33640, U.S. Strategic
Nuclear Forces: Background, Developments, and Issues, by Amy F. Woolf.
97 Office of the Secretary of Defense, Selected Acquisition Report (SAR): F-35 Joint Strike Fighter Aircraft (F-35),
March 17, 2019, p. 14.
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Cost and Funding98
Total Program Acquisition Cost99
As of December 2019, the most recent Selected Acquisition Report, the total estimated
acquisition cost (the sum of development, procurement, and military construction [MilCon] costs)
of the F-35 program in constant (i.e., inflation-adjusted) FY2012 dollars was about $321.4 billion,
including about $71.9 billion in research and development, about $245.0 billion in procurement,
and about $4.5 billion in MilCon.100
In then-year dollars (meaning dollars from various years that are not adjusted for inflation), the
figures are about $397.8 billion, including about $70.1 billion in research and development, about
$322.5 billion in procurement, and about $5.2 billion in military construction. That represents
approximately $30 billion less than projected the previous year.
Prior-Year Funding
Through FY2018, the F-35 program had received a total of roughly $150.6 billion of funding in
then-year dollars, including about $58.4 billion in research and development, about $89.2 billion
in procurement, and approximately $3.0 billion in military construction.
Unit Costs
As of December 2019, the F-35 program had a program acquisition unit cost (or PAUC, meaning
total acquisition cost divided by the 2,470 research and development and procurement aircraft) of
about $108.1 million and an average procurement unit cost (or APUC, meaning total procurement
cost divided by the 2,456 production aircraft) of $83.1 million, in constant FY2012 dollars.
However, this reflects the cost of the aircraft without its engine, as the engine program was
broken out as a separate reporting line in 2011.
As of December 2019, the F-35 engine program had a program acquisition unit cost of about
$22.1 million and an average procurement unit cost of $16.7 million in constant FY2012 dollars.
Just as the reported airframe costs represent a program average and do not discriminate among
the variants, those engine costs do not discriminate between the single engines used in the F-35A
and C and the more expensive engine/lift fan combination for the F-35B.
However, beginning in December 2016, DOD’s Selected Acquisition Reports broke out unit
recurring flyaway costs of the three engines as well as the separate airframes, as follows:

98 The F-35 program receives (or in the past received) funding from the Air Force, Navy, and Defense-Wide research,
development, test, and evaluation (RDT&E) accounts (the Defense-Wide RDT&E funding occurred in FY1996-
FY1998); Non-Treasury Funds (i.e., financial contributions from the eight other countries participating in the F-35
program)—a source of additional research and development funding; the Air Force and Navy aircraft procurement
accounts (the Navy and Marine Corps are organized under the Department of the Navy, and Marine Corps aircraft
development and procurement costs are funded through the Navy’s RDT&E and aircraft procurement accounts); and
the Air Force MilCon account and the Navy and Marine Corps MilCon account.
99 Figures in this section come from Office of the Secretary of Defense, F-35 Lightning II Joint Strike Fighter (JSF)
Program (F-35), December, 2019. This is the most recent Selected Acquisition Report issued for the program.
100 The procurement cost figure of about $245.0 billion does not include the cost of several hundred additional F-35s
that are to be procured other countries that are participating in the F-35 program. The figure does, however, assume
certain production-cost benefits for DOD aircraft that result from producing F-35s for other countries.
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Table 6. F-35 Projected Unit Recurring Flyaway Cost
(Assumes 802 international sales)
$M (2012)
F-35A
F-35B
F-35C
Airframe
57.4
72.1
72.3
Engine
10.7
26.3
10.8
Total
68.1
98.4
83.1
Source: Office of the Secretary of Defense, F-35 Lightning II Joint Strike Fighter (JSF) Program (F-35), December,
2019. This is the most recent Selected Acquisition Report issued for the program.
Note: Versions of this chart prior to FY2018 assumed 2443 U.S. sales and 612-673 international sales rather
than 2456/802.
Critics note that the costs reported in the Selected Acquisition Reports contain a number of
assumptions about future inflation rates, production learning curves, and other factors, and argue
that these figures do not accurately represent the true cost of developing and acquiring the F-
35.101
Other Cost Issues
Acquisition Cost and Long-Term Affordability
Over time, as the program has matured and unit costs have decreased in succeeding procurement
lots, attention on F-35 costs has shifted. The acquisition cost of the program is still large, and as
DOD considers the prospect of flat budgets for the future, other programs increasingly compete
with the F-35 for budget share. The Government Accountability Office, for example, has
increasingly questioned DOD’s ability to afford the current F-35 program given other demands
on budgets. This is a contrast to earlier reports, which focused more on the program’s ability to
meet its cost targets.
More recently, though, attention has moved to long-term affordability and sustainment costs, as
discussed below.
Unit Cost Projections
The F-35 program had long established a goal of making the F-35 cost-competitive with
previous-generation aircraft. (It should be noted that the articles cited below reference the cost of
the F-35A, the simplest model.)
F-35 fighter jets will sell for as little as $80 million in five years, according to the Pentagon
official running the program.
“The cost of an F-35A in 2019 will be somewhere between $80 and $85 million, with an
engine, with profit, with inflation,” U.S. Air Force Lieutenant General Christopher Bogdan,
the Pentagon’s manager of the program, told reporters in Canberra today.102

101 A detailed critique of the SAR figures with suggestions for alternatives appeared in Time magazine’s “Battleland”
blog. Authored by Winslow Wheeler of the Center for Defense Information, the most relevant entries are
http://nation.time.com/2013/06/04/alphabet-soup-paucs-apucs-urfs-cost-variances-and-other-pricing-dodges/ and
http://nation.time.com/2013/06/05/the-deadly-empirical-data/.
102 Jason Scott, “F-35s to Sell for as Low as $80 Million in 2019, Pentagon Says,” Bloomberg.com, March 11, 2014.
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That article dated from 2014. More recently, efforts were increased to reach the same target:
[Lockheed Martin] will invest up to $170 million over the next two years to extend its
existing “Blueprint for Affordability” measure ... to drive down the unit cost of an F-35A to
$85 million by 2019.103
As noted in Table 6, the average unit flyaway cost of an F-35A is officially projected at $80.6
million in constant 2012 dollars. However, according to the recent agreement on F-35 production
lot 11, an F-35A “is set to decrease from a Lot 11 price of $89.2 million to $82.4 million in Lot
12; $79.2 million in Lot 13; and $77.9 million in Lot 14.”104
Engine Costs
In 2013, engine maker Pratt & Whitney embarked on a program to reduce the F-35 engine’s
cost.105 Following release of data showing the “cost of acquiring the planned 2,443 airframes and
associated systems rose 1%, while engine costs climbed 6.7%,”106 the program manager
reportedly singled out Pratt for criticism “after having improved relations with the F-35’s prime
contractor, Lockheed Martin Corp., securing lower prices for each batch of new airframes and
closing deals far quicker than in the past.”107
Subsequently, Pratt & Whitney has signed contracts for engines through LRIP 11 that show a
steady percentage decrease in cost. The LRIP 11 announcement did not included a dollar figure
for the engines, instead citing percentage decreases in cost. “[Pratt & Whitney] is claiming
competitive privilege in its sole-source deal for F-35 engines in not releasing its actual
numbers.”108
Pratt says that “in general, the unit recurring flyaway (URF) price for the 110 LRIP Lot 11
conventional takeoff and landing and carrier variant propulsion systems will be
reduced 0.34 percent from the previously negotiated LRIP Lot 10 URF. The URF price for
the 25 LRIP Lot 11 short takeoff and vertical landing propulsion systems (including lift systems)
will be reduced 3.39 percent from the previously negotiated LRIP Lot 10 URF.”109
The issue of engine cost transparency is addressed in “Issues for Congress,” below.
Anticipated Upgrade Costs
The degree of concurrency in the F-35 program, in which aircraft are being produced while the
design is still being revised through testing, has made upgrades to early-production aircraft
inevitable. “For all F-35 variants, structural and durability testing led to significant discoveries

103 Valerie Insinna, “Lockheed Extends F-35 Cost-Cutting Initiative To Save Billions,” Defense News, July 11, 2016.
104 Valerie Insinna, “In newly inked deal, F-35 price falls to $78 million a copy,” Defense News, October 29, 2019,
https://www.defensenews.com/air/2019/10/29/in-newly-inked-deal-f-35-prices-fall-to-78-million-a-copy/.
105 Andrea Shalal, “Pratt must push harder to cut F-35 engine cost -Pentagon,” Reuters.com, April 7, 2014.
106 Doug Cameron, “Pentagon official criticizes Pratt & Whitney,” Marketwatch.com, April 17, 2014.
107 Ibid.
108 Ibid.
109 Pratt & Whitney, “Pratt & Whitney and F-35 Program Office Announce Contract Award for 135 F135 Engines,”
press release, May 31, 2018, https://utc.com/en/news/PW/2018/05/31/pratt-whitney-and-f-35-program-office-
announce-contract-award-for-135-f135-engi.
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requiring repairs and modifications to production designs, some as late as Lot 12 aircraft, and
retrofits to fielded aircraft.”110
The cost of those upgrades may vary, depending on what revisions are made during the testing
process. However, the cost of such upgrades is not included in the negotiated price of each
production lot.
The first F-35As, for example, were loaded with a basic software release (Block 1B) that provides
basic aircraft control, but does not have the degree of sensor fusion or weapons integration
expected in later blocks. “The initial estimate for modifying early-production F-35As from a
basic configuration to a capable warfighting level is $6 million per jet, plus other associated
expenses not included in that figure.”111 That would make the current cost of upgrading the
earliest F-35As to Block 3F about $100 million. In order to increase capability, the Air Force
intends to upgrade the aircraft step-by-step as new software releases become available rather than
waiting and jumping to the final release of Block 3F.
The cost of the major upgrade to Block 4 is discussed in “Issues for Congress,” below.
Operating and Support Costs
Since 2015, operations and sustainment costs for the F-35 fleet’s lifecycle have been estimated at
more than $1 trillion,112 “which DOD officials have deemed unaffordable. The program’s long
term sustainment estimates reflect assumptions about key cost drivers that the program does not
control, including fuel costs, labor costs, and inflation rates.”113 “The eye-popping estimate has
raised hackles at the Defense Department and on Capitol Hill since it was disclosed in 2011. It
covers the cost of fuel, spare parts, logistics support and repairs.”114 It may be worth noting that
“the F-35 was ... the first big Pentagon weapons program to be evaluated using a 50-year lifetime
cost estimate—about 20 years longer than most programs—which made the program seem
artificially more expensive.”115
The December 2018 F-35 Selected Acquisition Report spoke (in language unusual for that
document) to the need to reduce those costs:
At current estimates, the projected F-35 sustainment outlays based upon given planned
fleet growth will strain future service O&S budgets. (NB: The previous version had used
the words “are too costly.”) The prime contractor must embrace much-needed supply chain
management affordability initiatives, optimize priorities across the supply chain for spare
and new production parts, and enable the exchange of necessary data rights to implement
the required stand-up of planned government organic software capabilities.116

110 Director, Operational Test and Evaluation, FY2019 Annual Report, December 20, 2019, p. 23.
111 Gabe Starosta, “Block Upgrades For Earliest F-35s To Cost $6M Per Aircraft,” InsideDefense.com, March 26, 2014.
112 Office of the Secretary of Defense, Selected Acquisition Report (SAR): F-35, editions for December, 2011 through
December, 2019.
113 U.S. Government Accountability Office, F-35 JOINT STRIKE FIGHTER: Problems Completing Software Testing
May Hinder Delivery of Expected Warfighting Capabilities, GAO-14-322, March 2014, p. 12.
114 Sandra I. Erwin, “Next Battle for F-35: Bring Down Operations Costs,” National Defense
(nationaldefensemagazine.org), April 6, 2014.
115 Marine Corps Assistant Commandant for Aviation Lt. Gen. Terry Robling, cited in Andrea Shalal-Esa, “Lifetime
cost to run F-35 fighter: about $1 trillion,” Reuters.com, February 26, 2012.
116 Office of the Secretary of Defense, Selected Acquisition Report (SAR): F-35 Joint Strike Fighter Aircraft (F-35),
April 17, 2019, p. 10. See also Anthony Capaccio, “Lockheed Gets Edict to Cut F-35’s $1.1 Trillion Support Bill,”
Bloomberg News, April 5, 2018, https://www.bloomberg.com/news/articles/2018-04-05/pentagon-says-lockheed-must-
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A media report indicated that the Air Force was considering reducing its buy of F-35As due to its
support costs. “The shortfall would force the service to subtract 590 of the fighter jets from the
1,763 it plans to order ... the Air Force faces an annual bill of about $3.8 billion a year that must
be cut back over the coming decade.”117 “‘If you can afford to buy something but you have to
keep it in the parking lot because you can’t afford to own and operate it, then it doesn’t do you
much good,’ says [former] F-35 JPO Program Executive Officer Vice Adm. Mat Winter.”118 The
Air Force has subsequently begun acquiring the F-15EX fighter, in part arguing that its operating
costs are significantly lower than the F-35’s.119
Operations and sustainment costs as of the December 2019 Selected Acquisition Report were
reported at $630.5 billion in 2012 dollars (or $1.2 trillion in then-year dollars). It should be noted
that this estimate, provided by DOD’s Cost Assessment and Program Evaluation office, was not
updated from the December 2018 figure, and following language in the FY2020 National Defense
Authorization Act, DOD no longer publishes Selected Acquisition Reports.
“The operation and sustainment cost is a bigger issue,” (then-Air Force acquisition chief William)
LaPlante said. “It’s the one that will say whether or not we can afford (the F-35) in the longer
run.”120
Operations costs have been being addressed on several fronts, including changes in training,
basing, support, and other approaches.
To attack this problem, the F-35 program office in October 2013 set up a “cost war room”
in Arlington, Va.... A team of government and contractor representatives assigned to the
cost war room are investigating 48 different ways to reduce expenses. They are also
studying options for future repair and maintenance of F-35 aircraft in the United States and
abroad.121
The U.S. Air Force is looking to slash the number of locations where it will base F-35 Joint
Strike Fighter squadrons to bring down the jet’s estimated trillion-dollar sustainment
costs.... “When you reduce the number of bases from 40 to the low 30s, you end up reducing
your footprint, making more efficient the long-term sustainment,” David Van Buren, the
service’s acquisition executive, said in a March 2 exit interview at the Pentagon.122
More recently, “Lockheed, Northrop and BAE are also starting a ‘sustainment cost reduction
initiative’ aimed at cutting operations and maintenance expenses by 10 percent during fiscal 2018
through fiscal 2022. The vendors will invest $250 million and hope to reap at least $1 billion in
savings over five years.”123

keep-1-1-trillion-f-35-costs-down.
117 Anthony Capaccio, “Air Force Risks Losing Third of F-35s on Upkeep Costs,” Bloomberg News, March 28, 2018,
https://www.bloomberg.com/news/articles/2018-03-28/air-force-risks-losing-third-of-f-35s-if-upkeep-costs-aren-t-cut.
118 Lara Seligman, “F-35 Sustainment Challenges Mount As Global Fleet Grows,” Aviation Week and Space
Technology, April 5, 2018, http://aviationweek.com/defense/f-35-sustainment-challenges-mount-global-fleet-grows.
119 See also CRS In Focus IF11521, Air Force F-15EX Fighter Program.
120 Andrea Shalal, “U.S. focuses on cheaper, more reliable F-35 jet: Air Force official,” Reuters.com, April 1, 2014.
121 Sandra I. Erwin, “Next Battle for F-35: Bring Down Operations Costs,” National Defense
(nationaldefensemagazine.org), April 6, 2014.
122 Marcus Weisgerber, “USAF Eyes Deep Cuts To F-35 Bases,” Defense News, March 3, 2012.
123 Valerie Insinna, “Lockheed Extends F-35 Cost-Cutting Initiative To Save Billions,” Defense News, July 11, 2016.
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Manufacturing Locations
The F-35 is manufactured in several locations. Lockheed Martin builds the aircraft’s forward
section in Fort Worth, TX. Northrop Grumman builds the midsection in Palmdale, CA, and the
tail is built by BAE Systems in the United Kingdom.124 Final assembly of these components takes
place in Fort Worth. Final assembly and checkout facilities have also been established in Cameri,
Italy, and Nagoya, Japan.
The Pratt & Whitney F135 engine for the F-35 is produced in East Hartford and Middletown, CT.
Rolls-Royce builds the F-35B lift system in Indianapolis, IN.
Basing
On December 21, 2017, the Air Force announced Naval Air Station Joint Reserve Base Fort
Worth, TX, as the preferred alternative for the first F-35A reserve component base. Davis-
Monthan Air Force Base, AZ; Homestead Air Reserve Base, FL; and Whiteman AFB, MO, were
also candidate bases. At the same time, Truax Field, WI, and Dannelly Field, AL, were announced
as the next Air National Guard F-35A bases, with aircraft slated to arrive in 2023. Gowen Field
ANGB, ID; Selfridge ANGB, MI; and Jacksonville Air Guard Station, FL, were also considered.
Burlington Air National Guard Base, VT, had previously been selected.125
Active component F-35As had already been announced as going to Hill AFB, UT, and RAF
Lakenheath, England. Eielson AFB, AK, had earlier been announced as the preferred base for the
first overseas F-35 squadron.126 Luke AFB, AZ, and Eglin AFB, FL, are the main F-35 training
bases. F-35As also operate from Edwards AFB, CA, and Nellis AFB, NV.
In the United States, Marine F-35s are based at Marine Corps Air Stations Yuma, AZ, and
Beaufort, SC. Navy F-35s fly from Naval Air Stations Lemoore, CA, and Patuxent River, MD.
International Participation
In General
The F-35 program is DOD’s largest international cooperative program. DOD has actively pursued
allied participation as a way to defray some of the cost of developing and producing the aircraft,
and to “prime the pump” for export sales of the aircraft.127 Allies in turn view participation in the
F-35 program as an affordable way to acquire a fifth-generation strike fighter, technical
knowledge in areas such as stealth, and industrial opportunities for domestic firms.
Eight allied countries—the United Kingdom, Canada, Denmark, The Netherlands, Norway, Italy,
Turkey, and Australia—initially participated in the F-35 program under a Memorandum of
Understanding (MOU) for the SDD and Production, Sustainment, and Follow-On Development
(PSFD) phases of the program. These eight countries have contributed varying amounts of

124 CRS site visit to Palmdale, CA, March 10, 2016.
125 U.S. Air Force, “AF selects locations for next two Air National Guard F-35 bases,” press release, December 21,
2017, https://go.usa.gov/xQTRw.
126 Secretary of the Air Force Public Affairs, “Eielson AFB selected as preferred alternative for first overseas-based F-
35As,” press release, August 4, 2014, http://go.usa.gov/xxhNw.
127 Congress insisted from the outset that the JAST program include ongoing efforts by DARPA to develop more
advanced STOVL aircraft, opening the way for UK participation in the program.
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research and development funding to the program, receiving in return various levels of
participation in the program. International partners are also assisting with Initial Operational Test
and Evaluation (IOT&E), a subset of SDD.128 The partner countries are expected to purchase
hundreds of F-35s, with the United Kingdom’s 138 being the largest anticipated foreign fleet.129
Turkey’s participation in the F-35 program was subsequently curtailed after a disagreement with
the United States over its acquisition and intended fielding of a Russian air defense system.130 The
circumstances of that change are summarized below and described in CRS Report R44000,
Turkey: Background and U.S. Relations In Brief, and CRS Report R41368, Turkey: Background
and U.S. Relations, both by Jim Zanotti and Clayton Thomas.
Effects of Turkish Expulsion
Turkey’s removal affected the F-35 program in two principal areas. The first was a potential reduction in the
projected number of F-35s to be produced, although as other customers have appeared and the U.S. Congress
ordered Turkey’s F-35s be reallocated to the U.S. Air Force, the net effect has yet to be determined.
The other effects were the requirement to find replacements for the main engine overhaul facility for European F-
35s, which was to have been hosted in Turkey and wil now go to Norway and the Netherlands, and for Turkish
suppliers participating in the program, providing parts estimated at between $5 bil ion-$6 bil ion in value over 20
years.131
“According to U.S. officials, most of the supply chain handled by Turkish companies was due to move elsewhere
by March 2020, with a few contracts in Turkey continuing until later in the year. The cost of shifting the supply
chain, beyond some production delays, was estimated in July 2019 to be between $500 mil ion and $600
mil ion.”132
The Government Accountability Office found that, “[a]s of December 2019, the program has identified new
suppliers for all of these parts, but it stil needs to bring roughly 15 parts currently produced in Turkey up to the
current production rate…. According to an official with the Under Secretary of Defense for Acquisition and
Sustainment, by accepting parts from Turkish suppliers through lot 14, the program wil have additional time to
ensure new suppliers can meet demands for parts.”133
Two additional countries—Israel and Singapore—are security cooperation participants outside
the F-35 cooperative development partnership.134 Israel has agreed to purchase 33 F-35s, and may
want as many as 50.135 Japan chose the F-35 as its next fighter in October 2011, and formally

128 Currently, the UK, Italy, and the Netherlands have agreed to participate in the IOT&E program. UK, the senior F-35
partner, will have the strongest participation in the IOT&E phase. Italy and the Netherlands are contributing a far
smaller amount and will take part only in the coalition concept of operations (CONOPS) validation testing. (Telephone
conversation with OSD/AT&L, October 3, 2007.) Other partner nations are still weighing their option to participate in
the IOT&E program. The benefits to participation are expedited acquisition of aircraft, pilot training for the test cycle,
and access to testing results.
129 Gareth Jennings, “UK to approve bulk F-35B buy in 2017,” IHS Jane’s 360, February 6, 2014.
130 For more discussion, see CRS Report R41761, Turkey-U.S. Defense Cooperation: Prospects and Challenges, by Jim
Zanotti, and CRS Report R41368, Turkey: Background and U.S. Relations, by Jim Zanotti and Clayton Thomas.
131 “Procurement, Turkey,” Jane’s Sentinel Security Assessment - Eastern Mediterranean, December 16, 2010.
132 CRS Report R44000, Turkey: Background and U.S. Relations In Brief, by Jim Zanotti and Clayton Thomas.
133 U.S. Government Accountability Office, F-35 JOINT STRIKE FIGHTER: Actions Needed to Address
Manufacturing and Modernization Risks, GAO-20-339, May 2020, pp. 30-31, https://www.gao.gov/products/GAO-20-
339.
134 DOD offers Foreign Military Sales (FMS)-level of participation in the F-35 program for countries unable to commit
to partnership in the program’s SDD phase. Israel and Singapore are believed to have contributed $50 million each, and
are “Security Cooperative Participants.” (Selected Acquisition Report, Office of the Secretary of Defense for
Acquisition. December 31, 2005.)
135 Bob Cox, “Israeli government ok’s F-35 buy,” Fort Worth Star-Telegram, September 16, 2010. Yaakov Lappin,
“Israel, US Sign F-35 Agreement,” Jerusalem Post, October 8, 2010, and Lara Seligman, “Israeli Air Chief Asks For
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committed to 147 F-35Bs in August 2019.136 South Korea committed to the F-35 in 2014.137 As
noted earlier, Finland has decided to buy 64 and Switzerland 36. Sales to additional countries are
possible. Some officials have speculated that foreign sales of F-35s might eventually surpass
2,000 or even 3,000 aircraft.138
Sales to Israel, Japan, and South Korea are conducted through the standard Foreign Military Sales
process, including congressional notification. F-35 sales to nations in the consortium, conducted
under 22 U.S.C. 2767, are not reviewed by Congress.139
The UK is the most significant international partner in terms of financial commitment, and the
only Level 1 partner.140 On December 20, 1995, the U.S. and UK governments signed an MOU
on British participation in the JSF program as a collaborative partner in the definition of
requirements and aircraft design. This MOU committed the British government to contribute
$200 million toward the cost of the 1997-2001 Concept Demonstration Phase.141 On January 17,
2001, the U.S. and UK governments signed an MOU finalizing the UK’s participation in the SDD
phase, with the UK committing to spending $2 billion, equating to about 8% of the estimated cost

17 More F-35s,” Aerospace Daily & Defense Report, June 23, 2016.
136 Paul Kallender-Umezu, “Japan F-X Competition Win Victory for JSF Program,” Defense News, December 20,
2011. Ankit Panda, “Japan Officially Selects F-35B for Its STOVL Fighter,” The Diplomat, August 18, 2019,
https://thediplomat.com/2019/08/japan-officially-selects-f-35b-for-its-stovl-fighter/.
137 Choe Sang-hun, “South Korea Formally Announces Intent to Buy 40 Lockheed Fighter Jets,” The New York Times,
September 24, 2014.
138 Andrea Shalal-Esa, “Pentagon sees 6,000 possible F-35 sales,” Reuters.com, June 17, 2009. See also Marina
Malenic, “F-35 Sales Could Double As Countries Look To Replace Aging Fleets, General Says,” Defense Daily, June
18, 2009: 6, and Marcus Weisgerber, “JSF Program Anticipates Nearly 700 F-35 Buys [For International Customers]
Between FY-09 and FY-23, Inside the Air Force, July 31, 2009.
139 Correspondence to CRS from F-35 Joint Program Office, January 31, 2018. For more details on the Foreign Military
Sales process, see CRS In Focus IF11437, Transfer of Defense Articles: Foreign Military Sales (FMS), by Nathan J.
Lucas and Michael J. Vassalotti.
140 International participation in the F-35 program is divided into three levels, according to the amount of money a
country contributes to the program—the higher the amount, the greater the nation’s voice with respect to aircraft
requirements, design, and access to technologies gained during development. Level 1 Partner status requires
approximately 10% contribution to aircraft development and allows for fully integrated office staff and a national
deputy at director level.
Level II partners consist of Italy and the Netherlands, contributing $1 billion and $800 million, respectively. On June
24, 2002, Italy became the senior Level II partner (“F-35 Joint Strike Fighter (JSF) Lightning II: International
Partners,” http://www.globalsecurity.org/military/systems/aircraft/f-35-int.htm). Italy wants to have its own F-35 final
assembly line, which would be in addition to the existing F-35 maintenance and upgrade facility. The Netherlands
signed on to the F-35 program on June 17, 2002, after it had conducted a 30-month analysis of potential alternatives.
Australia, Denmark, Norway, Canada, and Turkey joined the F-35 program as Level III partners, with contributions
ranging from $125 million to $175 million. (“Australia, Belgium Enter Joint Strike Fighter Program as EMD Partners,”
Inside the Air Force, April 21, 2000.)
Unlike the SDD phase, PSFD phase does not make any distinction as to levels of participation. Also unlike the bilateral
SDD MOUs, there is a single PSFD MOU for all partner nations. In signing the PSFD MOU, partner nations state their
intentions to purchase the F-35, including quantity and variant, and a determination is made as to their delivery
schedule. PSFD costs will be divided on a “fair-share” based on the programmed purchase amount of the respective
nation. So-called “offset” arrangements, considered the norm in defense contracts with foreign nations, usually require
additional incentives to compensate the purchasing nation for the agreement’s impact to its local workforce. F-35
officials decided to take a different approach, in line with the program’s goal to control costs, to avoid offset
arrangements and promote competition as much as possible. Consequently, all partner nations have agreed to compete
for work on a “best-value” basis and have signed the PSFD MOU.
141 “U.S., U.K. Sign JAST Agreement,” Aerospace Daily, December 21, 1995, p. 451.
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of SDD. A number of UK firms, such as BAE and Rolls-Royce, participate in the F-35
program.142
International Sales Quantities
The cost of F-35s for U.S. customers depends in part on the total quantity of F-35s produced. As
the program has proceeded, some new customers have emerged, such as South Korea and Japan,
mentioned above. Other countries have considered increasing their buys, while some have
deferred previous plans to buy F-35s. It is perhaps noteworthy that the latest Selected Acquisition
Reports increased the number of assumed international sales for cost purposes from 612 to 802.143
Recent updates to other countries’ purchase plans are detailed in “Changes in International
Orders,” above.
Table 7. F-35 International Orders
Country
Quantity
Model(s)
Australia 144
100
A
Belgium 145
34
A
Denmark
27
A
Finland
64
A
Israel
50
A
Italy
90
60A / 30B
Japan 146
147
105 A / up to 42 B
Netherlands 147
46
A
Norway 148
52
A

142 BAE is a major partner to Lockheed Martin and is providing the aft fuselage, empennage, and electronic warfare
suite for the aircraft. Rolls-Royce is partnered with GE on the F136 engine and is a subcontractor to Pratt and Whitney
for producing components for the F-35B’s STOVL lift system. In October 2009, Rolls Royce broke ground on a new
plant in Virginia to make parts for the F136 engine. (Rolls Royce press release, “Rolls-Royce expands US capability;
begins construction on new manufacturing facility in Virginia,” October 19, 2009, available at http://www.rolls-
royce.com/investors/news/2009/091019_manufacturing_virginia.jsp.) Rolls Royce’s 2001 contract with Pratt and
Whitney for design and development of the STOVL lift components is valued at $1 billion over 10 years. (“Rolls-
Royce Finishes First JSF Propulsion System Flight Hardware,” Rolls-Royce Media Room, available at
http://www.rolls-royce.com/media/showPR.jsp?PR_ID=40243.) All F-35Bs, regardless of what engine they use, are to
employ Rolls Royce components in their STOVL lift systems.
143 Office of the Secretary of Defense, Selected Acquisition Report (SAR): F-35 Joint Strike Fighter Aircraft (F-35),
editions of 2016-2019.
144 “Two more Australian F-35s arrive at Luke AFB,” Australian Defence Magazine, May 31, 2019,
https://www.australiandefence.com.au/defence/air/two-more-australian-f-35s-arrive-at-luke-afb.
145 John A. Tirpak, “New F-35 Block Buy is Close, Lockheed Says,” Air Force, October 23, 2019,
https://www.airforcemag.com/new-f-35-block-buy-is-close-lockheed-says/.
146 White House Press Office, Remarks by President Trump and Prime Minister Abe of Japan in Joint Press
Conference, Tokyo, May 27, 2019, https://www.whitehouse.gov/briefings-statements/remarks-president-trump-prime-
minister-abe-japan-joint-press-conference-3/.
147 Sebastian Sprenger, “The Netherlands to buy nine more F-35s for $1.1 billion,” Defense News, October 8, 2019,
https://www.defensenews.com/global/europe/2019/10/08/the-netherlands-to-buy-nine-more-f-35s-for-11-billion/.
148 Government of Norway, Major Milestone: Norway declares IOC for F-35A, November 6, 2019,
https://www.regjeringen.no/en/aktuelt/major-milestone-norway-declares-ioc-for-f-35a/id2676740/, and Christopher
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Country
Quantity
Model(s)
Poland 149
32
A
South Korea 150
60
A
Singapore 151
4 with options for 8 more
B
Switzerland
36
A
United Kingdom
138
B
Total
888

Source: Lockheed Martin, at https://www.f35.com/f35/global-enterprise.html, modified by noted press reports.
The F-35 has won every major competition in which it was entered, most recently in Finland and
Switzerland. The only such competition remaining at the moment is in Canada, but Spain may
consider F-35Bs to maintain carrier operations as it begins to retire its F-18 Hornets late this
decade.
As noted, a significant question remains over whether Canada will continue as an F-35 partner. In
2015, the Trudeau government repudiated the previously announced purchase of 65 (which had
originally been 80), while remaining a formal partner in the program.152 A new competition for 88
jets is underway, with the F-35 and Saab Gripen remaining after the F-18’s elimination.153
Lockheed Martin has stated that if Canada withdraws as a customer, Canadian work share will
suffer.154
Work Shares and Technology Transfer
DOD and foreign partners in the JSF program have occasionally disagreed over the issues of
work shares and proprietary technology. For example, the United States rejected a South Korean
request for transfer of four F-35 technologies that could assist in the development of a Korean
indigenous fighter program (although 21 other technologies were approved).155

Dennis, “US officials welcome Norway’s new F-35 capabilities in an increasingly competitive Northern Europe,” Stars
and Stripes, November 27, 2019, https://www.stripes.com/news/europe/us-officials-welcome-norway-s-new-f-35-
capabilities-in-an-increasingly-competitive-northern-europe-1.608872.
149 Bartosz Glowacki, “Poland signs F-35 contract worth $4.6bn,” FlightGlobal, January 31, 2020,
https://www.flightglobal.com/defence/poland-signs-f-35-contract-worth-46bn/136476.article, and U.S. Mission Poland,
Poland’s Purchase of F-35 Fighters, Warsaw, January 31, 2020, https://pl.usembassy.gov/purchase_f35/. Defense
Security Cooperation Agency, Poland – F-35 Joint Strike Fighter Aircraft, Washington, DC, September 11, 2019,
https://www.instapaper.com/read/1285363759.
150 Jeff Jeong, “South Korea to buy 20 more F-35 jets,” Defense News, October 10, 2019,
https://www.defensenews.com/global/asia-pacific/2019/10/10/south-korea-to-buy-20-more-f-35-jets/.
151 John Geddie and Aradhana Aravindan, “U.S. State Dept. approves sale of 12 F-35 jets to Singapore,” Reuters,
January 10, 2020, https://www.reuters.com/article/us-singapore-defence-lockheed/u-s-state-dept-approves-sale-of-12-f-
35-jets-to-singapore-idUSKBN1Z90G9.
152 Lee Berthiaume, “Liberals fork over another $30 million to keep Canada at F-35 table,” Canadian Press, May 25,
2017, http://www.cbc.ca/news/politics/f-35-fighter-jet-joint-strike-canada-fee-1.4131285.
153 David Ljunggren, “Canada tells Boeing its bid for C$19 bln fighter jet contract falls short - source,” Reuters,
November 25, 2021, https://www.reuters.com/business/aerospace-defense/canada-rules-boeing-out-c19-bln-fighter-jet-
contract-canadian-press-2021-11-25/.
154 Aaron Mehta, “No System in Place To Strip Canadian F-35 Participation,” Defense News, July 11, 2016.
155 Jung Sung-ki, “Tech Transfer Hobbles South Korea’s Fighter Program,” Defense News, September 27, 2015, and
Jon Grevatt, “US approves F-35 offset technology transfer to South Korea,” IHS Jane’s Defence Industry, December
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The governments of Italy and the United Kingdom have lobbied for F-35 assembly facilities to be
established in their countries. In July 2010, Lockheed and the Italian firm Alenia Aeronautica
reached an agreement to establish an F-35 final assembly and checkout facility at Cameri Air
Base, Italy, to deliver aircraft for Italy and the Netherlands. The facility opened in July 2013.156 A
similar facility has opened in Nagoya, Japan, with the first aircraft delivered in 2017.157 Norway
and the Netherlands will host engine overhaul and logistics facilities Turkey had been scheduled
to until its exclusion from the program.
Proposed FY2022 Budget
Table 8 shows the Administration’s FY2022 request for Air Force and Navy research and
development and procurement funding for the F-35 program, along with FY2020 and FY2021
funding levels. Table 9 shows the procurement request in greater detail.
Table 8. FY2022 F-35 Funding Request
(Figures in millions of then-year dollars)
FY2020
FY2021
FY2022 (request)

Funding
Quantity
Funding
Quantity
Funding
Quantity
RDT&E funding

Dept. of Navy
726.3
—
720.9
—
998.5

Air Force
727.1
—
815.9
—
1,054.8

Subtotal
1,453.4
—
1,536.8
—
2,053.3

Procurement funding

Dept. of Navy
4,419.6
34
4,576.8
36
4,831.3
37
Air Force
5,903.6
62
6,217.6
60
4,520.2
48
Subtotal
10,323.1
96
10,794.4
96
9,351.6
85
Mods
410.5

554.4

619.5

TOTAL
12,187.1
96
12,885.6
98
12,024.3
85
Source: Program Acquisition Costs by Weapons System, Office of the Under Secretary of Defense
(Comptrol er)/Chief Financial Officer, May 2021.
Note: Figures shown do not include funding for MilCon funding or research and development funding provided
by other countries.
Table 9. FY2022 F-35 Procurement Request
(All dollars in millions)
F-35A
F-35B
F-35C

Quantity
48
17
20
Procurement cost
4,714.8
2,517.5
2,388.8
Less previous advance procurement
547.2
260.8
280.2
Subtotal
4,167.6
2,256.7
2,108.6

21, 2016.
156 Craig Hoyle, “An Italian view on the F-35,” Flightglobal.com/DEW Line blog, August 7, 2013.
157 Amy Butler, “First F-35 Assembled In Italy To Roll Out Early Next Year,” Aerospace Daily and Defense Report,
December 10, 2014, and David Cenciotti, “The First Japanese-Built F-35A Unveiled At Nagoya Production Facility In
Japan,” The Aviationist, June 5, 2017, https://theaviationist.com/2017/06/05/the-first-japanese-built-f-35a-unveiled-at-
nagoya-production-facility-in-japan/.
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F-35A
F-35B
F-35C

Advance procurement for future aircraft
352.6
216.8
249.1
Spares
267.7
79.2
113.8
Total FY21 request
4,520.2
2,473.5
2,357.8
Average procurement cost per aircraft
98.2
148.1
119.4
Source: February 2021 DOD justification books.
Issues for Congress
Overall Need for F-35
The F-35’s cutting-edge capabilities are accompanied by significant costs. Some analysts have
suggested that upgrading existing aircraft might offer sufficient capability at a lower cost, and that
such an approach makes more sense in a budget-constrained environment. Others have produced
or endorsed studies proposing a mix of F-35s and upgraded older platforms; yet others have
called for terminating the F-35 program entirely. Congress has considered the requirement for F-
35s on many occasions and has held hearings, revised funding, and added oversight language to
defense bills. As the arguments for and against the F-35 change, the program matures, and/or the
budgetary situation changes, Congress may wish to consider the value of possible alternatives,
keeping in mind the program progress thus far, funds expended, evolving world air environment,
and the value of potential capabilities unique to the F-35.
Planned Total Procurement Quantities
A potential issue for Congress concerns the total number of F-35s to be procured. As mentioned
above, planned production totals for the various versions of the F-35 were left unchanged by a
number of reviews. Since then, considerable new information has appeared regarding cost growth
and budget constraints that may challenge the ability to maintain the expected procurement
quantities. “’I think we are to the point in our budgetary situation where, if there is unanticipated
cost growth, we will have to accommodate it by reducing the buy,’ said Undersecretary of
Defense Robert Hale, then Pentagon comptroller.”158
Some observers, noting potential limits on future U.S. defense budgets, potential changes in
adversary capabilities, and competing defense-spending priorities, have suggested reducing
planned total procurement quantities for the F-35. A September 2009 report on future Air Force
strategy, force structure, and procurement by the Center for Strategic and Budgetary Assessments,
for example, states that
[A]t some point over the next two decades, short-range, non-stealthy strike aircraft will
likely have lost any meaningful deterrent and operational value as anti-access/area denial
systems proliferate. They will also face major limitations in both irregular warfare and
operations against nuclear-armed regional adversaries due to the increasing threat to
forward air bases and the proliferation of modern air defenses. At the same time, such
systems will remain over-designed – and far too expensive to operate – for low-end
threats....

158 Marina Malenic, “DoD Comptroller: Further F-35 Cost Growth Jeopardizes Buy Quantity,” Defense Daily, March
4, 2010.
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Reducing the Air Force plan to buy 1,763 F-35As through 2034 by just over half, to 858
F-35As, and increasing the [annual F-35A] procurement rate to end [F-35A procurement]
in 2020 would be a prudent alternative. This would provide 540 combat-coded F-35As on
the ramp, or thirty squadrons of F-35s[,] by 2021[, which would be] in time to allow the
Air Force budget to absorb other program ramp ups[,] like NGB [the next-generation
bomber, B-21].159
Block 4/C2D2 as a Separate Program
Development of the F-35 Block 4 software, part of an effort now called Continuous Capability
Development and Delivery (C2D2), is expected to cost as much as $10.8 billion over the next six
years.160 “The F-35 Joint Program Office (JPO) plans to transition into the next phase of
development – Continuous Capability Development and Delivery (C2D2) – beginning in CY18,
to address deficiencies identified in Block 3F development and to incrementally provide planned
Block 4 capabilities.”161
“The JPO’s latest plan for F-35 follow-on modernization ... C2D2, relies heavily on agile
software development—smaller, incremental updates to the F-35’s software and hardware instead
of one big drop, with the goal of speeding follow-on upgrades while still fixing remaining
deficiencies in the Block 3F software load.”162
Some in Congress argue that a program of that size should part with traditional procurement
practice for an upgrade and be run as a separate Major Defense Acquisition Program (MDAP),
with its own budget line and the concomitant requirements. At a March 23, 2016, hearing of a
House Armed Services subcommittee
Government Accountability Office (GAO) Director of Acquisition and Sourcing
Management Michael Sullivan argued that the Block 4 estimated cost justifies its
management as a separate program, but F-35 Program Executive Officer (PEO) Air Force
Lt. Gen. Christopher Bogdan countered that breaking it off would create an administrative
burden and add to the program’s price tag and schedule.163
The House-passed version of the FY2020 National Defense Authorization Act (H.R. 2500)
contained a provision (§132) that would require the Secretary of Defense to designate the C2D2
program as a major subprogram of the F-35 program. An enacted into law, the act (P.L. 116-92)
does not designate Block 4 and/or C2D2 as a major subprogram, but requires the Secretary of
Defense to submit an annual integrated master schedule and past performance assessment for
each planned phase of Block 4 and C2D2 upgrades.

159 Thomas P. Ehrhard, An Air Force Strategy for the Long Haul, Washington, Center for Strategic and Budgetary
Assessments, 2009, pp. xii and xiv. The report was released on September 17, 2009, according to CSBA’s website, and
is available at http://www.csbaonline.org/4Publications/PubLibrary/R.20090917.An_Air_Force_Strat/
R.20090917.An_Air_Force_Strat.pdf. Subsequent to writing this report, the author became a special assistant to the Air
Force Chief of Staff.
160 Pat Host, “Pentagon faces major cost increase on F-35 Block 4 modernisation,” IHS Jane’s Defence Weekly, March
8, 2018, http://janes.ihs.com/Janes/Display/1830607.
161 Director, Operational Test and Evaluation, FY 2017 Annual Report, Washington, DC, January 2018, p. 31,
http://www.dote.osd.mil/pub/reports/FY2017/.
162 Lara Seligman, “What F-35 Can Learn From F-22 Upgrade Hiccups,” Aviation Week and Space Technology, March
28, 2018, http://aviationweek.com/defense/what-f-35-can-learn-f-22-upgrade-hiccups.
163 Valerie Insinna, “Bogdan: Separate Program For F-35 Block 4 Mods Would Increase Cost, Schedule Difficulties,”
Defense Daily, March 24, 2016.
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An emerging issue is the continued oversight of Block 4. As GAO noted in May 2020, delays in
the program mean that the Block 4 effort is now likely to last longer than its congressional
reporting requirement. 164 The National Defense Authorization Act of 2017 (P.L. 114-328)
included language requiring annual reports on the progress of Block 4 through 2023. As the
program is now projected to continue through 2026, Congress may wish to consider extending
that requirement or other oversight measures.
Competition
Lieutenant General Bogdan’s comments regarding the difficulty of cost control in a sole-source
environment (see “Engine Costs,” above) reflect a broader issue affecting defense programs as
industry consolidates and fewer sources of supply are available for advanced systems. Congress
may wish to consider the merits of maintaining competition when overseeing system
procurements (for example, the use of competition to maintain cost pressure was a principal
argument in favor of the F-35 alternate engine program).165 On the F-35 program, that
competition could include contracting for lifecycle support as a way to address sustainment costs.
Appropriate Fighter Mix
A significant issue, beginning with the FY2020 DOD budget submission, is the optimal mix of
fighter aircraft in the Air Force fleet. Previous plans had focused on the F-35 as the mainstay of
the future fighter fleet, in keeping with an Air Force initiative to move to an all-fifth-generation-
and-beyond force. In FY2020, however, the Air Force requested an initial 8 of a projected buy of
144 F-15EX fighters. The F-15EX is an improved version of the F-15 Eagle and Strike Eagle
fighter series, which the United States last acquired in 2001.166
Subsequently, the Air Force justified the request on two grounds: that the operating costs of the F-
35 were significantly higher than fourth-generation aircraft like the F-15EX, and that the service
needed to acquire 72 new fighters per year to maintain its fleets as older aircraft retire.167
The Air Force has maintained that F-35 and F-15EX do not compete directly for funding.
Observers note that, regardless, the F-15EX proposal came at a time when the Air Force reduced
its planned F-35 buy from 60 to 48 jets per year. Further, some argue that the additional
capabilities inherent in the F-35 provide a better value at similar cost.168 F-15 advocates note the

164 U.S. Government Accountability Office, F-35 JOINT STRIKE FIGHTER: Actions Needed to Address
Manufacturing and Modernization Risks, GAO-20-339, May, 2020, pp. 31-32, https://www.gao.gov/products/GAO-20-
339.
165 For more on this issue, see CRS Report R41131, F-35 Alternate Engine Program: Background and Issues for
Congress.
166 For more on this issue, see CRS Insight IN11078, Proposed Air Force Acquisition of New F-15EXs.
167 Valerie Insinna, “The US Air Force doesn’t want F-15X. But it needs more fighter jets,” Defense News, February
28, 2019, https://www.defensenews.com/digital-show-dailies/air-warfare-symposium/2019/02/28/the-air-force-doesnt-
want-f-15x-but-it-needs-more-fighter-jets/. Oriana Pawlyk, “Air Force Wants Both F-35 and F-15EX. But if Forced to
Choose, It’s No Contest: SecAF,” Military.com, May 20, 2019, https://www.military.com/daily-news/2019/05/20/air-
force-wants-both-f-35-and-f-15ex-if-forced-choose-its-no-contest-secaf.html.
168 See, for example, John Venable, The F-35A Is the World’s Most Dominant, Cost-Effective Fighter: The Air Force
Needs to Accelerate Its Acquisition Now, The Heritage Foundation, Washington, DC, March 2, 2020,
https://www.heritage.org/defense/report/the-f-35a-the-worlds-most-dominant-cost-effective-fighter-the-air-force-needs-
0.
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age of current U.S. F-15s, and that new F-15EXs offer better value than extending the lives of
existing ones.169
More recently, the Air Force has been considering replacing some F-16s, which had been
expected to be replaced by F-35s, with unmanned systems instead.
[Air Combat Command commander Gen. Mike] Holmes suggested that low-cost and
attritable unmanned aircraft systems (UAS) might be considered… as a replacement for F-
16 Block 25/30 jets… within 5-8 years. In congressional testimony on March 12, Holmes
added that ACC’s goal is to achieve a fighter fleet ratio of 60% fifth-generation jets, such
as F-35As and F-22s, to 40% fourth-generation aircraft, including F-15s, F-16s and A-
10s.170
That ratio had previously been expressed as 50-50.171
Engine Cost Transparency
In the specific case of the F-35, Pratt & Whitney and the Joint Program Office have declined to
reveal the cost per engine in each LRIP contract, replacing dollar costs with percentage savings
and aggregate contract values that include items other than the engines themselves. Congress may
wish to consider whether this approach is sufficient to provide useful oversight, and weigh that
value against a contractor’s right to protect competition-sensitive data. A possible analogue can be
found in the debate over whether public disclosure of the contract value for the B-21 bomber
might reveal more data than prudent, or whether that revelation is a reasonable cost to allow
proper program oversight.
Acquiring Advanced Engines
Congress directed in the FY2022 National Defense Authorization Act (P.L. 117-81) that the
military services publish strategies to procure advanced adaptive powerplants for the F-35 (see
the “Adaptive Engine Transition Program” section above). However, as the engines will not be
common across the F-35 fleet, costs for each service’s version may pose challenges to the service
budgets. Commonality and concomitant savings were a significant selling point of the F-35
program. Congress may wish to consider the tradeoff between enhanced performance and higher
cost.172
Affordability
An additional potential issue for Congress for the F-35 program concerns the affordability of the
F-35, particularly in the context of projected shortfalls in both Air Force fighters and Navy and
Marine Corps strike fighters.

169 Brian Everstine, “NORTHCOM Stresses Importance of F-15EX Buy for Homeland Defense,” Air Force Magazine,
March 12, 2020, https://www.airforcemag.com/northcom-stresses-importance-of-f-15ex-buy-for-homeland-defense/.
170 Steve Trimble, “As USAF Fleet Plans Evolve, Can the F-35A Program Survive Intact?,” Aviation Week, March 19,
2020, https://aviationweek.com/defense-space/usaf-fleet-plans-evolve-can-f-35a-program-survive-intact.
171 Valerie Insinna, “The US Air Force doesn’t want F-15X. But it needs more fighter jets,” Defense News, February
28, 2019, https://www.defensenews.com/digital-show-dailies/air-warfare-symposium/2019/02/28/the-air-force-doesnt-
want-f-15x-but-it-needs-more-fighter-jets/.
172 See, inter alia, John A. Tirpak, “Adding New AETP Engine to F-35 Means Air Force Alone Would Pay for It,” Air
Force Magazine, September 1, 2021, https://www.airforcemag.com/adding-new-aetp-engine-f-35-air-force-alone-
would-pay-for-it/.
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Although the F-35 was conceived as a relatively affordable strike fighter, some observers are
concerned that in a situation of constrained DOD resources, F-35s might not be affordable in the
annual quantities planned by DOD, at least not without reducing funding for other DOD
programs. As the annual production rate of the F-35 increases, the program will require more than
$10 billion per year in acquisition funding at the same time that DOD will face other budgetary
challenges. The issue of F-35 affordability is part of a larger and long-standing issue concerning
the overall affordability of DOD’s tactical aircraft modernization effort, which also includes
procurement of F/A-18E/Fs, increasingly capable unmanned aerial vehicles, and, as mentioned,
F-15EXs.173
Implications for Industrial Base
Another potential issue for Congress regarding the F-35 program concerns its potential impact on
the U.S. tactical aircraft industrial base. The award of the F-35 SDD contract to a single company
(Lockheed Martin) raised concerns in Congress and elsewhere that excluding Boeing from this
program would reduce that company’s ability to continue designing and manufacturing fighter
aircraft.174
Similar concerns regarding engine-making firms have been raised since 2006, when DOD first
proposed (as part of the FY2007 budget submission) terminating the F136 alternate engine
program. Some observers are concerned that if the F136 were cancelled, General Electric would
not have enough business designing and manufacturing fighter jet engines to continue competing
in the future with Pratt & Whitney (the manufacturer of the F135 engine). Others argued that
General Electric’s considerable business in both commercial and military engines was sufficient
to sustain General Electric’s ability to produce this class of engine in the future.
Exports of the F-35 could also have a strong impact on the U.S. tactical aircraft industrial base
through export. Most observers believe that the F-35 could potentially dominate the combat
aircraft export market, much as the F-16 has. Like the F-16, the F-35 appears to be attractive
because of its relatively low cost, flexible design, and promise of high performance. Competing
fighters and strike fighters, including France’s Rafale, Sweden’s JAS Gripen, and the Eurofighter
Typhoon, are positioned to challenge the F-35 in the fighter export market.
Some observers are concerned that by allowing foreign companies to participate in the F-35
program, DOD may be inadvertently opening up U.S. markets to foreign competitors who enjoy
direct government subsidies. A May 2004 GAO report found that the F-35 program could
“significantly impact” the U.S. and global industrial base.175 GAO found that two laws designed
to protect segments of the U.S. defense industry—the Buy American Act and the Preference for
Domestic Specialty Metals clause—would have no impact on decisions regarding which foreign
companies would participate in the F-35 program, because DOD has decided that foreign
companies that participate in the F-35 program, and which have signed reciprocal procurement
agreements with DOD to promote defense cooperation, are eligible for a waiver.

173 For more on this issue, see CRS Report RL33543, Tactical Aircraft Modernization: Issues for Congress.
174 For more information, see CRS Report RL31360, Joint Strike Fighter (JSF): Potential National Security Questions
Pertaining to a Single Production Line, by Christopher Bolkcom and Daniel H. Else (out of print; available to
congressional clients from the author upon request).
175 General Accounting Office, Joint Strike Fighter Acquisition: Observations on the Supplier Base, GAO-04-554, May
2004.
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Future Joint Fighter Programs
Congress consolidated the JAST and ASTOVL programs after finding “no apparent willingness
or commitment by the Department to examine future needs from a joint, affordable, and
integrated warfighting perspective.”176 DOD states that the F-35 program “was structured from
the beginning to be a model of acquisition reform, with an emphasis on jointness, technology
maturation and concept demonstrations, and early cost and performance trades integral to the
weapon system requirements definition process.”177 A subsequent RAND Corporation study
found that the fundamental concept behind the F-35 program—that of making one basic airframe
serve multiple services’ requirements—may have been flawed.178 Congress may wish to consider
how the advantages and/or disadvantages of joint programs may have changed as a consequence
of evolutions in warfighting technology, doctrine, and tactics.

176 U.S. Congress, House Committee on National Security, National Defense Authorization Act for Fiscal Year 1996,
report to accompany H.R. 1530, 104th Cong., 1st sess., June 1, 1995, H.Rept. 104-131.
177 Department of Defense. Selected Acquisition Report (SAR)[for] F-35 (JSF), December 31, 2007, p. 4.
178 Mark A. Lorell, Michael Kennedy, Robert S. Leonard, Ken Munson, Shmuel Abramzon, David L. An, Robert A.
Guffey, Do Joint Fighter Programs Save Money?, RAND Project Air Force, Santa Monica, CA, 2013,
http://www.rand.org/pubs/monographs/MG1225.html.
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Appendix. F-35 Key Performance Parameters
Table A-1 summarizes key performance parameters for the three versions of the F-35.
Table A-1. F-35 Key Performance Parameters (KPPs)
F-35A
F-35B
F-35C
Source
Air Force
Marine Corps
Navy carrier-
of KPP
KPP
CTOL version
STOVL version
suitable version
Joint
Radio frequency
Very low observable
Very low observable Very low observable
signature

Combat radius
590 nm
450 nm
600 nm
Air Force mission
Marine Corps
Navy mission profile
profile
mission profile

Sortie generation
3 surge / 2 sustained
4 surge / 3 sustained 3 surge / 2 sustained

Logistics footprint
< 8 C-17 equivalent
< 8 C-17 equivalent
< 46,000 cubic feet,
loads (24 PAA)
loads (20 PAA)
243 short tons

Mission reliability
93%
95%
95%

Interoperability
Meet 100% of critical, top-level information exchange requirements;
secure voice and data
Marine
STOVL mission
n/a
550 feet
n/a
Corps
performance –
short-takeoff
distance

STOVL mission
n/a
2 x 1K JDAM,
n/a
performance –
2 x AIM-120,
vertical lift bring-
with reserve fuel
back
Navy
Maximum approach
n/a
n/a
145 knots
speed
Source: F-35 program office, October 11, 2007.
Notes: PAA is primary authorized aircraft (per squadron); vertical lift bring back is the amount of weapons with
which plane can safely land.

Author Information

John R. Hoehn

Analyst in Military Capabilities and Programs

Acknowledgments
Jeremiah Gertler, former Specialist in Military Aviation, originally authored this report.
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Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan
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under the direction of Congress. Information in a CRS Report should not be relied upon for purposes other
than public understanding of information that has been provided by CRS to Members of Congress in
connection with CRS’s institutional role. CRS Reports, as a work of the United States Government, are not
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