Air Force Fighter Force Structure: Background and Issues for Congress

Air Force Fighter Force Structure: Background and Issues for Congress

Air Force Fighter Force Structure: Background and Issues for Congress

September 4, 2026 (R49338)
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Contents

Introduction

Background

Size and Evolution of the Air Force Fighter Fleet

Selected Statutory Provisions

10 U.S.C. §9062—Policy; Composition; Aircraft Authorization

10 U.S.C. §9062a—Annual Report on the Air Force Fighter Aircraft Force Structure

2025 Fighter Force Structure Report

Methodology, Definitions, and Risk Framework

Fleet Condition and Planned Force Mix as of 2025

Force Structure Objective and Feasibility

Readiness, Sustainment, and Workforce Risks

Air National Guard Engagement

Issues for Congress

Goal of 1,558 Tactical Fighters

Resourcing and Authorizing the Fleet

Multiyear Procurement Authority

Aircraft Retirements

Readiness

Pilot Training and Supply

Industrial Constraints

Air National Guard

Summary

Since the U.S. Air Force's establishment in the National Security Act of 1947 (P.L. 80-253, Title II, §207), Congress has provided oversight of the size and composition of Air Force aircraft fleet. The service's aircraft fleet includes tactical fighter aircraft for various missions, including air-to-air combat, air-to-ground attack, air interdiction, suppression or destruction of enemy air defenses, close air support, strike control and reconnaissance, combat search and rescue support, and airborne forward air control.

U.S. fighter inventories have varied across eras, reflecting changes in strategic demands, operational concepts, technology, and aircraft complexity. During World War II, the U.S. Army Air Forces fought a two-front global war and worked with defense contractors to build more than 100,000 fighters. During the Cold War, technological advancements made fighter aircraft more capable. The Air Force maintained smaller inventories while leveraging foreign military sales to allied air forces to bolster coalition airpower and interoperability. The Air Force fleet in 2025 contained what the service calls "legacy aircraft" (e.g., F-16, F-15) equipped with engines designed for high maneuverability and speed and advanced radar and weapons, as well as "fifth-generation" (e.g., F-22 and F-35) fighter aircraft differentiated by stealth features, electronic warfare capability, and improved avionics. Potential threats in the Pacific theater would require aircraft to operate at longer ranges and to counter advanced air defense and electronic warfare threats. In consideration of such requirements, the Air Force is developing more advanced fighter aircraft that could operate with collaborative combat aircraft affordable enough to buy in large numbers.

Congress in Title 10, Section 9062, of the U.S. Code requires the U.S. Air Force to maintain a total primary mission aircraft inventory of not less than 1,145 fighter aircraft. Congress also has established a statutory requirement in Title 10, Section 9062a, of the U.S. Code for the service to submit annual reports on the fighter force structure. In October 2025, the Air Force transmitted to Congress the report Long-Term USAF Fighter Force Structure, which outlined a new approach to counting the total number of fighter aircraft in its fleet. In this report, the Air Force stated that it

does not expect to meet in FY2026 Congress's fighter force size requirement;

operates a heavily used and aging fleet, with an average aircraft age of 27.4 years;

seeks to retire older aircraft and purchase annually up to 24 F-15EXs by 2027 and 100 F-35s by 2030;

plans for the development of the sixth-generation F-47 fighter to reach a goal of 1,558 fighters by 2035;

intends to use uncrewed collaborative combat aircraft to enhance operation of, but not replace, manned fighter aircraft;

faces potential constraints on production capacity, readiness, sustainment, and its workforce; and

is considering how to modernize Air National Guard and Air Force Reserve units.

Potential considerations for Congress regarding the Air Force's fighter force structure plans may include

whether to support, oppose, or modify the service's goal of obtaining 1,558 crewed fighters by 2035; this may include consideration of the sufficiency of information available for overseeing the cost of developing, acquiring, and maintaining the fighter force, as well as whether to provide more, less, or the same level of funding requested for developing, acquiring, and maintaining the fighter force;

how to exercise oversight of plans for quantifying and/or integrating uncrewed aircraft into the force;

whether to support, oppose, or modify the service's plans to retire older fighter aircraft to a specified inventory level and the implications of those decisions for force structure, readiness, and capability;

how to address certain readiness issues, including Air Force pilot and maintainer shortages and limited training time and industrial base constraints in supply chains, spare parts, and the workforce; and

how to resolve potential differences in approaches to modernizing Reserve Force fighter fleets.

Introduction¹

Congress plays a role in funding, authorizing, and overseeing the size and makeup of the U.S. Air Force (USAF), including its fighter aircraft, in part through annual defense authorization and appropriations acts. Section 9062 of Title 10 of the U.S. Code requires the Secretary of the Air Force to maintain through October 1, 2026, "a total primary mission aircraft inventory (combat-coded) of not less than 1,145 fighter aircraft," with primary mission aircraft inventory defined as "aircraft assigned to meet the primary aircraft authorization to a unit for the performance of its wartime mission."² Fighter aircraft is defined as an aircraft designated with an F- or A- prefix; manned by one or two crewmembers; and capable of executing air-to-air combat, air-to-ground attack, air interdiction, suppression or destruction of enemy air defenses, close air support, strike control and reconnaissance, combat search and rescue support, or airborne forward air control.³ The Servicemember Quality of Life Improvement and National Defense Authorization Act for Fiscal Year 2025 (FY2025 NDAA; P.L. 118-159) established Title 10, Section 9062a, of the U.S. Code, which requires the Secretary of the Air Force to submit to congressional defense committees an unclassified report regarding USAF's tactical fighter aircraft force structure no later than April 1, 2025, and annually through 2030. Some Members of the 119th Congress have expressed interest in issues covered in this annual report submitted by the Department of the Air Force (DAF), including current inventory and planned modernization programs and force sufficiency and risk.⁴ Some Members have introduced legislation that would revise the total inventory requirements in Title 10, Section 9062, of the U.S. Code authorize multiyear procurement of F-15EX and F-35 fighters, and/or increase the size of the F-15EX fleet by 200 aircraft.⁵

In October 2025, DAF transmitted to the congressional defense committees a report titled Long-Term USAF Fighter Force Structure (2025 DAF report).⁶ The report, which included a classified annex, indicates that in FY2026, USAF primary mission aircraft inventory (PMAI) was expected to fall below the statutory minimum number of 1,145 tactical fighters (see "Methodology, Definitions, and Risk Framework" in this report).⁷ The 2025 DAF report proposed changing PMAI to what the Air Force called "Combat Coded Total Aircraft Inventory (CC TAI), which would include backup aircraft inventory and attrition reserve aircraft.⁸ USAF reported that procuring fighters in larger numbers could increase the fighter inventory from 1,098 aircraft in FY2026 to 1,558 aircraft in FY2035 to achieve an acceptable level of risk to operations in support of the National Military Strategy.⁹ The report stated that national defense priorities, including homeland defense, deterrence, and power projection, informed the service's stated quantity for CC TAI. According to the report, the quantity reflected the "desired overall USAF possessed inventory," not "procurement targets."¹⁰ To reach its goal, USAF proposed continuing to divest older fighter aircraft, prioritizing next-generation fighter and uncrewed aircraft development, and increasing F-35 and F-15EX production. The Air Force is not currently meeting the statutory requirement; on May 5, 2026, Secretary of the Air Force Troy E. Meink notified Congress that USAF had 1,098 fighters in its fighter inventory and was below the required PMAI of 1,145 aircraft.¹¹

Congress may accept, reject, or modify USAF's long-term tactical fighter aircraft force structure through further oversight activity, policy, provision of funding in annual defense authorization and appropriations acts, and other actions. Potential oversight considerations include the proposed force structure's level of risk; its cost relative to broader USAF and Department of Defense (DOD, which is "using a secondary Department of War designation," under Executive Order 14347 of September 5, 2025) budget requirements; the availability of personnel to operate and sustain the force; and the capacity of the industrial base to meet proposed production rates. Congress may consider the pace at which to incorporate uncrewed collaborative combat aircraft (CCA) into the fleet. Congress may also consider whether U.S. military operations in Iran, among other activities, potentially support or challenge the assumptions underlying the 2025 DAF report.

Background

Size and Evolution of the Air Force Fighter Fleet

The USAF active fighter inventory has decreased since its peak in the 1940s following shifts in strategic demands, threat perceptions, technological advances, and budgetary conditions.¹²

During World War II, the United States financed production of more than 100,000 so-called first- or second-generation fighter aircraft.¹³ These fighters (e.g., P-51, P-38) were powered by propellers, controlled manually, and equipped with bombs and machine guns to carry out aerial combat and bomber escort missions.¹⁴ While inventory began to decline in the postwar years, the beginning of the Cold War led the United States to build up what some authors called "the most capable and advanced fighter [research and development] industrial base in the world."¹⁵ The fleet was dominated initially by the F-4 Phantom supersonic fighter-bomber with a range of up to 1,750 miles. By 1968, the fleet contained 4,729 active fighter aircraft.¹⁶

In the late 1960s and 1970s, the military's focus shifted to regional conflicts. The Pentagon responded by pursuing a mix of fighters that paired the F-15, a long-range air superiority fighter designed to establish control of contested airspace, with the more agile and less expensive F-16 that could be procured in larger quantities.¹⁷

After the end of the Cold War, in 1991, fighter inventories declined to approximately 3,939 aircraft as U.S. defense policy supported a so-called "peace dividend" whereby resources that had been applied for defense could be used for other purposes, and force planning increasingly emphasized technological advantage, regional contingencies, and reduced force structure.¹⁸ Following Operation Desert Storm in Iraq in 1991, successive U.S. defense reviews prioritized regional contingencies rather than global peer conflict, a planning assumption that factored into decisions to reduce fighter inventories, even as USAF continued to conduct research into advanced aircraft.¹⁹

The number of Air Force fighter aircraft continued to decrease in the post-9/11 era, a period marked by additional resourcing for ground forces and operations in Iraq and Afghanistan, and procurement of newer aircraft lagged retirements of older aircraft. By 2003, the USAF fighter inventory was approximately 2,431 aircraft.²⁰ During this decade, USAF sought to "transform to a smaller, more capable force."²¹ The service developed a mix of F-22 Raptors for air superiority and F-35 multi-role Joint Strike Fighters, which the United States developed with a coalition of international partners. Some observers view both types of aircraft as representing fifth-generation fighter technology, which broadly includes characteristics such as stealth coatings and shaping to evade radar detection, advanced radar and sensors, and integrated avionics.²² In 2009, the then Defense Secretary Robert Gates proposed truncating the purchase of F-22 Raptors at 187 as part of a broader effort to identify billions of dollars in savings and efficiencies and redirecting resources to other programs.²³ Some defense analysts argued at the time that the decision—which some in Congress supported—could lead to U.S. fighters being outnumbered by People's Liberation Army Air Force (PLAAF) aircraft in a potential 2020 Taiwan strait contingency.²⁴

The Budget Control Act of 2011 (BCA; P.L. 112-25), as amended, established defense spending caps over a 10-year period through FY2021. This decade saw additional fighter force structure reductions and modernization delays. By 2013, the USAF fighter inventory totaled approximately 2,091 aircraft.²⁵ Despite certain technological advantages relative to potential adversaries, including China and Russia, USAF stated that it accepted increased risk (to operational support) by procuring fewer aircraft per year and training fewer pilots (than previous levels).²⁶

In 2025, USAF continued purchasing an advanced version of the F-15 (i.e., F-15EX) and the F-35 and continued developing a new generation of fighters. USAF awarded a contract to Boeing to build the F-47 Next Generation Air Dominance aircraft, which some have described as a sixth-generation fighter. The service has ongoing competitions for companies to develop collaborative combat aircraft, so-called uncrewed "wingmen" that could be procured to address range and payload limitations of crewed aircraft. At the same time, some analysts tracking China's fighter jet production assessed that rapid growth in production of China's J-20 fifth-generation stealth fighter could increase the PLAAF's inventory of J-20 fighters to around 1,000 by 2030.²⁷

In its 2025 report, DAF identified a need for 1,558 combat-coded (CC) crewed fighters—excluding uncrewed aircraft, or drones—by 2035 to achieve a low-risk operational posture, which generally refers to a level of risk assessed as acceptable without requiring additional risk-reduction measures such as accepting decreased readiness, stress on the force, or the inability to respond to combatant commander requirements.²⁸ On May 5, 2026, Secretary of the Air Force Meink notified Congress that USAF had 1,098 fighters in its fighter inventory and was below the statutory requirement of 1,145 aircraft.²⁹

A July 2026 Congressional Budget Office (CBO) report projected that the Air Force fighter fleet would continue to decline until 2030 and then begin to grow.³⁰ The report adds that the average age of the Air Force fleet has "crested and will decline until the early 2030s."³¹

Analysts have expressed differing views related to the number of fighter aircraft USAF might need for current and future operational requirements, especially relative to emergent weapons and technologies.³² Noting the use of low-cost drones in Iran, Ukraine, and elsewhere, as well as the development of artificial intelligence, some have asserted that the U.S. military should consider capability metrics other than the number of crewed aircraft.³³

Selected Statutory Provisions

10 U.S.C. §9062—Policy; Composition; Aircraft Authorization

As noted, the USAF force structure requirements are established in Section 9062 of Title 10 of the U.S. Code, which has been amended to adjust inventory requirements and limitations, as well as set policies. The statute directs the Secretary of the Air Force to "maintain a total aircraft inventory of fighter aircraft of not less than 1,800 aircraft, and a total primary mission aircraft inventory (combat-coded) of not less than 1,145 fighter aircraft" through October 1, 2026.³⁴

The statute prohibits USAF from retiring F-22 aircraft or decreasing the inventory below 184 aircraft through September 30, 2027; as of August 2026, the service has 185 F-22s.³⁵ It prohibits USAF from retiring more than 51 F-15E aircraft and states that no F-15E aircraft may be retired in FY2026, no more than 21 F-15Es may be retired in FY2027, and no more than 30 F-15Es may be retired in FY2028.³⁶

The FY2026 NDAA (P.L. 119-60, §344) added a requirement for the Secretary of the Air Force to report to the armed services committees proposed actions to reverse the decline in aircraft (with an emphasis on fighter aircraft) readiness, along with annual reports on the implementation of the proposed actions for three subsequent years.

10 U.S.C. §9062a—Annual Report on the Air Force Fighter Aircraft Force Structure

The statute—established by the FY2025 NDAA (P.L. 118-159, §142) and amended by the FY2026 NDAA (P.L. 119-60, §144)—directs the Secretary of the Air Force "in coordination with" the Director of the Air National Guard (ANG) and the Commander of the Air Force Reserve Command to develop a 10-year tactical fighter aircraft force structure, recapitalization, training, and sustainment plan annually through 2030 for the active and reserve components of the Air Force, along with a report to the congressional defense committees.

2025 Fighter Force Structure Report

Methodology, Definitions, and Risk Framework

The Air Force's force structure assessment for the 2025 report relied on service-developed analysis, war gaming, and the Chairman of the Joint Chiefs of Staff's Risk Assessment framework.³⁷ The report categorized aircraft to support its analysis, with unmanned systems assessed separately and excluded from manned fighter inventory totals.³⁸ The report evaluated force structure sufficiency using DOD definitions of military risk and assessed the probability of failing to achieve operational objectives (risk-to-mission) and the stress placed on forces (risk-to-force).³⁹ Under planning guidance from the Joint Chiefs of Staff, "moderate risk" is generally accepted as the standard, meaning forces can meet most requirements but may experience strain in sustained operations.⁴⁰

A central methodological change in the report is the transition from PMAI to Combat-Coded Total Aircraft Inventory (CC TAI). Under PMAI-based reporting, USAF counted only aircraft assigned to primary missions and excluded backup aircraft and attrition reserves that helped to sustain operations. USAF stated that the prior approach omitted approximately 15% of aircraft assigned to CC units.⁴¹ By contrast, according to USAF, CC TAI includes primary mission aircraft, backup aircraft, and attrition reserves, thus providing a more comprehensive measure of combat capacity.⁴² USAF stated that this methodology also accounts for maintenance downtime and attrition, which would be necessary in times of high-intensity conflict.⁴³

Fleet Condition and Planned Force Mix as of 2025

The 2025 DAF report described the USAF fighter fleet as heavily utilized and aging, with an average aircraft age of approximately 27.4 years.⁴⁴ In 1994, the overall Air Force fleet was an average of 17.2 years old—with an availability rate of 72.9%. In 2024, the fleet was 31.7 years old and available 53.9% of the time.⁴⁵ The Air Force found that this correlation between aircraft age and declining availability contributed to increased sustainment costs and operational risk.⁴⁶ To address these challenges, the report proposed a fleet that could balance legacy aircraft (A-10, F-15, and F-16 fighters), fifth-generation aircraft (e.g., F-35 and F-22—modern fighter aircraft designed with stealth, advanced sensors, and the ability to operate in highly contested environments), and emerging platforms (e.g., F-47).⁴⁷ The report noted that divestment of older aircraft was intended to reduce sustainment burden and reallocate resources toward systems with greater capability and availability.⁴⁸

Legacy Fleet

A-10. The A-10 is a single-seat, dual-engine aircraft designed for close-air support and combat search and rescue missions. The A-10 Thunderbolt II has been in operation since 1976.⁴⁹ The 2025 DAF report shared that USAF planned to complete divestment of the A-10 fleet by the end of FY2026, according to the direction of the Office of the Secretary of Defense.⁵⁰ A social media post attributed to the Air Force Secretary on April 20, 2026, stated that USAF would continue to operate the aircraft through 2030.⁵¹ In a May 5, 2026, memorandum, Secretary of the Air Force Meink stated that USAF planned to extend the use of 36 A-10s through 2030.⁵²

F-15C/D, E, EX.⁵³ The F-15, first operational in 1975, is a multi-role fighter that can be operated in a single- or dual-seat configuration.⁵⁴ USAF described plans to divest the F-15C/D fleet through approximately 2030, with some of the older aircraft identified to support airspace control authority missions.⁵⁵ The F-15E fleet is undergoing partial divestment of older engine variants to improve readiness and sustainment activities.⁵⁶ The 2025 DAF report stated that the service intends to procure additional F-15EX aircraft (newer variants upgraded with advanced radar and electronic warfare suites). The report projected production of up to 24 F-15EX aircraft annually beginning in FY2027 to address near-term capacity requirements, offset retirements, and sustain fighter inventory stability.⁵⁷ The Air Force's FY2027 budget has requested funding to procure 24 F-15EXs in FY2027 and FY2028, increasing to 36 of the Boeing aircraft by FY2030.⁵⁸

F-16C/D. The F-16 is a compact, multi-role fighter available in single- or dual-seat models. It was declared operational in 1979.⁵⁹ USAF said the F-16 is positioned to continue fulfilling both homeland defense and theater missions. According to the 2025 DAF report, USAF is pursuing what it calls "post-block modernization," or incremental packages of hardware or software improvements applied to aircraft over time (i.e., radar, datalink, and electronic warfare upgrades), as a means to extend the operational relevance of these aircraft while avoiding the higher sustainment risk associated with older platforms.⁶⁰ Lockheed Martin makes an advanced version of the F-16, the Block 70/72, for export to foreign countries.⁶¹ An April 2025 report to Congress, Sustainment and Recapitalization of the Air National Guard Fighter Fleet, assessed the potential to develop a U.S. version of the F-16 Block 70/72 aircraft to replace aging F-16s and found that development would require four to five years and $925 million.⁶²

Fifth-Generation Fleet

F-22, F-35. The F-22 is a stealthy twin-engine fighter designed for air superiority (i.e., the ability to operate without threat of attack, even in highly contested environments). The F-35 is a stealthy single-engine, multi-role fighter.⁶³ The 2025 DAF report describes fifth-generation fighters as the foundation of the future force due to their survivability and ability to operate in contested environments.⁶⁴ According to the report, USAF plans partial divestment of F-22 Block 20 aircraft while modernizing Block 30/35 variants to sustain air superiority capability as a bridge to the Next Generation Air Dominance fighter (F-47). USAF identified the F-35 as a procurement and modernization priority due to its multi-role capabilities, which USAF views as critical to future joint operations.⁶⁵ According to FY2027 budget documents, the Air Force has requested $3.1 billion for the purchase of 24 F-35s in discretionary funding and $2.3 billion for 14 additional F-35s in mandatory funding.⁶⁶ Long-term budget projections indicate the service may request 48 F-35s by 2030, which is fewer than the report's stated annual goal.⁶⁷

Emerging Platforms

The 2025 DAF report stated that F-47s and CCAs (uncrewed aircraft designed to operate alongside manned fighters) are USAF's "number one modernization priority" for the fighter portfolio.⁶⁸

F-47. The report said that the F-47 Next Generation Air Dominance fighter is a central enabler for future high-end conflict. Details on future quantities, timelines, and basing appear to be contained in a classified report annex.⁶⁹ According to FY2027 budget documents, the Air Force has requested $5 billion in research, development, test, and evaluation (RDT&E) funding for the F-47 program.⁷⁰

CCAs. The 2025 DAF report identified CCAs (YQF-42 and YQF-44) as components of the future fighter force that are intended to augment—rather than replace—manned fighters by enhancing survivability, expanding sensor coverage, and increasing capacity at lower cost.⁷¹ CCAs are expected to operate initially with fifth-generation fighters and later as part of the Next Generation Air Dominance family of systems.⁷² According to FY2027 budget documents, the Air Force is seeking $1.4 billion in RDT&E funds for the CCA program.⁷³

Advanced Synthetic Training. The report identified the Joint Simulation Environment (JSE) as a unique resource for high-end training and testing and tactics development. The JSE is a highly realistic virtual environment enabling pilots and systems to train against advanced threats. Compared with live exercises, the JSE is described as a more practical venue for replicating contested environments at scale.⁷⁴ As constraints on flying hours, pilot availability, and range access persist, advanced synthetic training is expected to play an increasingly central role in defense strategy.⁷⁵ According to FY2027 budget documents, the Air Force has requested $302.8 million in RDT&E funds for the JSE program.⁷⁶

Force Structure Objective and Feasibility

USAF risk analysis concluded that the service requires 1,558 manned CC TAI fighters to achieve a low-risk operational posture by 2035.⁷⁷ The report identified an interim objective of approximately 1,369 manned CC TAI by 2030 while acknowledging that budget and production capacity constraints may limit USAF's ability to meet the requirement.⁷⁸ According to the report, achievement of these targets would require maximum procurement rates of approximately 100 F-35A and 24 F-15EX aircraft per year in 2030.⁷⁹

The report emphasized that such inventory goals are not to be interpreted as direct procurement requirements.⁸⁰ Replacement of aging aircraft, early-lot obsolescence, and modernization limitations may drive shortfalls in inventory that would later necessitate larger procurement quantities to sustain effective combat capability. For example, F-35 technical challenges have in the past affected the utility of earlier aircraft lots and the pace of production.⁸¹

USAF production projections assume funding, consistent supplier performance, and sufficient industrial base capacity.⁸² Although current production lines could increase fighter production, aircraft deliveries typically lag procurement by several years. Additionally, production delays may also delay procurement decisions and then operational availability, which may affect the pace at which inventory growth translates into combat capability.⁸³ These production timelines reflect multiyear processes—including manufacturing, testing, delivery, and unit integration—that could affect force structure size.

International demand is another factor potentially affecting delivery of aircraft to the U.S. military. Boeing is reportedly increasing production of the F-15EX—on a production line shared with foreign military sales (FMS) customers.⁸⁴ Lockheed Martin reported that it delivered 191 F-35 aircraft in 2025 to USAF, the U.S. Navy, and international customers.⁸⁵ Plans to increase the USAF allotment of F-35 fighters or other aircraft could compete with foreign military sales customers for the same aircraft.⁸⁶

Readiness, Sustainment, and Workforce Risks

Fighter aircraft readiness (i.e., the ability of an aircraft to fly a training or operational mission) is influenced by sustainment, personnel, and training factors that collectively determine capability rates.⁸⁷ The 2025 DAF report identified multiple interrelated risks that may affect USAF's ability to generate and sustain combat-ready forces.

Sustainment

USAF reported that annual sustainment costs have increased by approximately $950 million since FY2019 and per-aircraft costs increasing by more than 18%.⁸⁸ At the same time, the report identified an annual shortfall of roughly $400 million in weapon system sustainment funding relative to projected requirements.⁸⁹ The Air Force FY2027 budget requested $4.4 billion in spare parts for all USAF aircraft.⁹⁰

Pilot Availability and Training

USAF reported that the Flying Hour Program—the number of hours pilots fly each year—is used to maintain pilot proficiency and readiness and supports both tactical development and operational integration.⁹¹ In the report, USAF emphasized the need to "train how we fight," while acknowledging trade-offs between flying hours, modernization priorities, and budget constraints.⁹²

Pilot shortages remain a challenge for the service. In FY2024, the then Vice Chief of Staff of the Air Force General James C. Slife stated that USAF was 1,900 pilots short of the 19,136 pilots that the service identified as needed for global requirements.⁹³ USAF has a goal of producing approximately 1,500 pilots annually through the Undergraduate Pilot Training program. A House Armed Services Committee report (H.Rept. 119-231) accompanying the committee-reported version of an FY2026 NDAA (H.R. 3838) noted that the service had not met the target. ⁹⁴

The 2025 DAF report noted challenges associated with pilot shortages, training bottlenecks, and manpower limitations, characterizing these issues as largely outside the scope of the force structure assessment.⁹⁵ The report acknowledged that aircraft inventory growth alone does not guarantee increased combat capability if personnel and training capacity do not keep pace.⁹⁶

To minimize disruptions during recapitalization, the report outlined a series of planned actions, including squadron transitions, phased modernization, new training programs for aircrew and maintainers, and planning for basing and infrastructure requirements.⁹⁷

Air National Guard Engagement

The 2025 DAF report described proposed changes to Air National Guard (ANG) and Air Force Reserve fleets, including the retirement of nearly all F-15C/Ds and their replacement with the F-35, F-15EX, or the F-16 Block 40/50.⁹⁸ The Air Force Reserve would retire two A-10 units in 2026 and maintain two F-35 units.⁹⁹

ANG-affiliated organizations have expressed concern that the migration of the ANG force from aging F-15C/Ds and early F-16 variants is not moving fast enough and have asserted that, absent timely replacement of older aircraft, multiple ANG fighter squadrons could face loss of airframes and associated missions.¹⁰⁰

In testimony, the Chief of the National Guard Bureau General Steven Nordhaus emphasized the importance of "concurrent recapitalization" with the active-duty Air Force, adding that modernizing Air National Guard fighter fleets with such aircraft as the F-35 and F-15EX was central to sustaining the "lethality" and "interoperability" of the component.¹⁰¹

Issues for Congress

USAF's proposed fighter force structure plan raises potential issues for Congress regarding the size, capability, affordability, and feasibility of achieving planned inventory levels.

Goal of 1,558 Tactical Fighters

One issue for Congress is whether to accept, reject, or modify the USAF goal of obtaining 1,558 CC fighters by 2035. A related issue is whether to accept, reject, or modify the proposed method of counting those aircraft.

The version of an FY2027 NDAA passed by the House (H.R. 8800) would amend Title 10, Section 9062, of the U.S. Code to direct the Secretary of the Air Force to "maintain a total aircraft inventory of combat-coded fighter aircraft of—(i) not less than 1,369 aircraft by December 31, 2030; and (ii) not less than 1,558 aircraft by December 31, 2035."¹⁰²

The House provision would extend the requirement for maintaining the total inventory of fighters at 1,800, as currently defined in the statute, and extend the requirement from October 1, 2026, to October 1, 2035. It would also increase the total planned procurement of F-15EX fighters to "beyond 267 aircraft."¹⁰³

An FY2027 NDAA (S. 4784) version approved by the Senate Armed Services Committee (SASC) would also extend the requirement for a total aircraft inventory of 1,800 fighter aircraft through October 1, 2035. It would modify the Title 10, Section 9062, requirement to mandate a "total inventory of combat-coded" fighter aircraft of "not less than" 1,369 aircraft by December 31, 2030.¹⁰⁴ The SASC proposal would define "combat-coded" as an aircraft that is

(i) assigned to a combat-designated operational squadron or unit for the performance of its wartime mission;

(ii) formally categorized within the Department of the Air Force inventory management system as primary mission aircraft inventory, backup aircraft inventory, or attrition reserve; and

(iii) resourced and maintained to provide immediate operational capacity and the necessary organic depth required to sustain combat mission effectiveness through modernization cycles, scheduled and unscheduled maintenance, and combat attrition.¹⁰⁵

Both the House and SASC versions of an FY2027 NDAA would exclude CCAs from the fighter inventory. In negotiating a final version of an FY2027 NDAA, Congress may choose to accept, reject, or modify these proposals to amend Title 10, Section 9062, of the U.S. Code.

Congress may also consider how the change to CC TAI proposed in the DAF force structure report may affect funding and/or requirements for other costs of maintaining squadrons of aircraft and consider whether to make a corresponding adjustment in the numeric requirement for fighter aircraft. Some analysts have reportedly said that the change in counting TAI would exacerbate readiness issues.¹⁰⁶

Congress may consider oversight issues in assessing whether to support USAF's reported goal. Potential oversight questions include the following:

What combat scenarios did USAF consider in arriving at its stated goal?

What specific risks might arise or not arise from a small fleet size? How might USAF mitigate potential national security risks before it reaches its fighter force structure goal?

To what extent did USAF consider its goal in the context of other DOD assets or in the context of adversary air fleets?¹⁰⁷

How might recent operations in Iran, Ukraine, and elsewhere affect USAF plans to reach its force structure goal or its current and future plans to incorporate additional uncrewed aircraft into its inventory and at what pace? What would be the risks and benefits of such changes?

Some observers argue that a change in how TAI is calculated could mask personnel shortfalls.¹⁰⁸ How might the proposed method of counting inventory impact the number of or readiness of pilots or maintainers? How might the change in calculation affect the ability of the Air Force to resource TAI requirements?

The F-35 program serves USAF as well as the Navy, Marine Corps, and 19 international customers that are also awaiting delivery of aircraft. How might an annual Air Force order of 100 F-35s impact the flow of aircraft to other customers? USAF has stated that it could require expansion of production or reallocation from other customers. How might such a change affect the Navy, international alliances, or the capability and security of those customer nations?

Advanced fighter aircraft development programs—such as the F-35 and the F-22—ran behind schedule and over budget. How reliable are development timelines for the F-47? Is the Air Force incorporating any lessons learned from the F-35 and F-22 programs to the F-47 program? If so, which lessons? How might the relative accuracy of those estimates affect future fighter force structure plans?

Uncrewed Aircraft

The Air Force goal of 1,558 fighters pertains to crewed aircraft. Both the House and SASC versions of the NDAA would continue to exclude CCAs from tactical fighter inventory. With increased use of uncrewed fighters, among other emerging technologies, in strike roles in Ukraine and Iran, some analysts have proposed revising existing metrics for quantifying fighter forces.¹⁰⁹

Congress may consider a number of questions relating to uncrewed aircraft: What impact, if any, does the introduction of uncrewed CCAs have on such goals and requirements for fighter inventory? What assumptions, if any, did USAF make about CCAs or uncrewed aircraft systems in planning its fighter inventory, and might this affect future statutory requirements for tactical fighter aircraft? Under what conditions, if any, might USAF consider adding CCAs or other uncrewed aircraft to the statutory requirement for fighter aircraft? USAF is also proposing the Massed Modular Aircraft program—uncrewed aircraft focused on ISR and strike missions.¹¹⁰ An introduction of these new platforms into the service's fleet may affect discussions about the size of the Air Force's tactical fighter inventory.

Resourcing and Authorizing the Fleet

Although USAF noted that its goal of obtaining 1,558 fighters was not a procurement target, the report stated that the classified annex presents the maximum procurement and production of fighters "with no fiscal constraints."¹¹¹ Congress may consider whether to approve, reject, or modify Air Force procurement plans for fighter aircraft.

Some analysts have said that purchasing 74 F-35As each year would require an additional $3.7 billion annually, which analysts say could be achieved with a ramp-up in production from 42 F-35s in FY2025, to 54 jets in FY2026, 66 jets in FY2027, and 72 jets in FY2028.¹¹² If USAF were to seek funding for such a production increase, Congress could choose to approve, reject, or modify such a request. DOD released a preliminary FY2027 discretionary budget request to Congress seeking $2.9 billion to procure 24 F-35s for USAF.¹¹³

If Congress sought to support the Air Force's inventory goals, one potential option could be to direct the service to move money within USAF to fund future procurement of up to 100 F-35s annually by FY2030 and 24 F-15EXs annually by FY2027, which might necessitate funding reductions elsewhere (in defense or nondefense programs). Another potential option could be to increase funding for the Air Force relative to the other military services, which could provoke internal opposition and/or external political constraints.

Multiyear Procurement Authority

Congress may consider other options, including the use of multiyear procurement authority. The House-passed and SASC-reported FY2027 NDAA would authorize the Secretary of Defense to sign multiyear procurement contracts for F-15EX and F-35 fighters.¹¹⁴

The multiyear contracting authority provided by SASC for the F-15EX is contingent on whether the contractor, in this case Boeing, can increase production to help the Air Force achieve an inventory of 268 F-15EX aircraft by 2035. The authority provided by HASC would also include spare parts in the contract.

Congress may consider whether to approve, reject, or modify the conditions placed on those authorities and whether to support funding requests for future multiyear contracts. Members may weigh the relative risks and potential savings associated with this contracting approach.

Aircraft Retirements

The 2025 DAF report stated that restrictions on USAF's ability to divest aircraft "decreases overall aircraft availability rates and directly impacts operational readiness."¹¹⁵ Some Air Force uniformed leaders have noted that older aircraft break down more often and cost more to maintain than newer aircraft; in addition, obtaining spare parts for older aircraft can be difficult.¹¹⁶

Congress has restricted certain aircraft retirements in the past. Some reasons for such restrictions are that such divestment could limit the force's ability to respond to operational needs; cause pilots and maintainers to leave National Guard units without flying missions; and eliminate unique capabilities such as those provided by the A-10 Thunderbolt II.¹¹⁷

For example, Title 10, Section 9062, of the U.S. Code contains provisions prohibiting retirement of F-22 aircraft through the end of FY2027 and F-15E aircraft through the end of FY2028.¹¹⁸ Congress has placed multiple restrictions on the planned retirement of A-10 aircraft, most recently in the FY2026 NDAA (P.L. 119-60, §147), which required the Air Force to maintain a minimum TAI of 103 A-10s through September 30, 2026. The FY2026 NDAA also required USAF to brief the armed services committees by March 31, 2026, on plans to divest each A-10 unit prior to FY2029.¹¹⁹ The Air Force FY2027 budget request shelved plans to completely divest the fleet of A-10s, though it plans to continue to retire F-15C/D and F-16 C/D aircraft and speed the ramp-up of F-15EX production. Congress may consider whether to support Air Force plans to divest certain aircraft, amend divestment restrictions, or add new restrictions and reporting requirements for future force structure plans. The House-passed version of an FY2027 NDAA would extend the prohibition on F-22 retirements through September 31, 2032.¹²⁰

Readiness

According to the Government Accountability Office (GAO), Air Force readiness levels decreased over a six-year period ending in FY2023. Between FY2018 and FY2023, two aircraft—the F-15C and the F-16C—met annual goals for mission capability. GAO attributes "this shortage to numerous interrelated, complex factors, such as aging aircraft, maintenance challenges, and supply support issues."¹²¹ News reporting based on USAF-provided data stated that aircraft mission capable rates had dropped further—to 67.15% in FY2024.¹²²

Pilot Training and Supply

As described in the DAF report, the CC TAI number reflects the possession of aircraft and the ability to generate and sustain combat operations over time. Therefore, assumptions regarding aircraft inventory growth implicitly depend on corresponding growth in pilot production, training throughput, and assignment. Persistent pilot shortages and training bottlenecks could therefore constrain USAF's ability to translate increased fighter inventories into fully staffed, combat-ready units.

Congress may consider requesting information to assess the Air Force's programs for training pilots and providing flight hours. In the context of the fighter force structure plan, Congress may consider posing oversight questions, including the following:

What crew ratios, or number of trained personnel available to operate each aircraft expressed as the number of pilots per aircraft, did USAF assume?

What is the required annual pilot production rate to sustain 1,558 aircraft?

What are requirements for maintainer manpower?

S. 4784 would provide incentive packages aimed at retaining experienced pilots.¹²³ Congress may consider whether to adopt, modify, or reject such proposals.

Industrial Constraints

Spare Parts

According to the Department of Defense Appropriations Act, 2026 (P.L. 119-75, Division A), joint explanatory statement, Congress appropriated $1.19 billion for parts, including $220 million for the F-35 and its F135 engine to address readiness concerns stemming from the lack of spare parts for fighter aircraft. The HASC report (H.Rept. 119-231) accompanying the committee-reported FY2026 NDAA noted the risk to fighter aircraft readiness posed by parts shortages across all services and directed the Comptroller General to review supply chain risks and spare parts availability. Congress may consider the results of that review and whether the current cost factors considered in estimating the cost of spare parts is adequate or not.¹²⁴ Congress may or may not consider whether to provide additional funding for spare parts.

Industrial Workforce

Some organizations have said that some aerospace companies have reported difficulty in hiring engineers and predicted that aerospace assembly lines may experience workforce shortages in the next decade.¹²⁵ Congress may consider providing oversight of the industrial base workforce to assess the extent to which USAF is factoring potential impacts from workforce shortages into its plan to increase aircraft (and missile) production and sustainment. Congress may consider whether existing programs to attract and retain aerospace engineers and workers are adequate to the needs of the aerospace industrial base.

Air National Guard

The FY2026 NDAA (P.L. 119-60, §144) amendment to Title 10, Section 9062a(a), of the U.S. Code changed Secretary of the Air Force engagement with the Director of the ANG from "consultation" to "coordination." The provision did not define "coordination" or require concurrence of the director. The language may signal congressional intent for a more structured and documented role for the ANG in developing and submitting the annual fighter force structure report. According to the 2025 DAF report, extending the reporting requirement through 2030 provides Congress additional oversight visibility during this modernization window, and the shift from "consultation" to "coordination" may influence how DAF documents transition timelines, ANG-specific impacts, and internal coordination processes in future annual submissions.

Some ANG units conduct homeland defense and aerospace control alert missions; the sequencing of divestments and replacement deliveries may affect these units' readiness and mission continuity.

Congress may consider the ANG's recommendations for cascading aircraft into the Reserve Component and the pace at which that occurs. Congress may also consider whether to further study development of an upgraded F-16 for ANG forces, whether or not an upgraded F-16 would be relevant to current operational needs, whether the cost of such an upgrade would be relative to buying other types of existing fighter aircraft—such as the F-15EX or F-35—and the length of the time it would take to obtain an upgrade.

In an April 1, 2026, letter to the leaders of the Senate and House Committees on Appropriations, 22 Adjutants General (who oversee ANG units within states) said they are seeking funding for multiyear procurement of annual F-35A and F-15EX aircraft to ensure that the 13 F-16 squadrons in the ANG scheduled to receive F-16s of different types are instead replaced by F-35 or F-15EX fighters.¹²⁶ The HASC report (H.Rept. 119-698) to accompany the committee-reported version of an FY2027 NDAA acknowledges ANG concerns about aging F-15C and other fighter aircraft and directs the Secretary of the Air Force to brief HASC on a plan for fielding the F-15EX and F-35A to Air National Guard installations. An amendment adopted in the House-passed version of an FY2027 NDAA would require the Secretary of Defense to submit to the congressional defense committees a comprehensive plan for the recapitalization of the F-16 aircraft of the 140th Wing of the Colorado ANG.¹²⁷ Congress may or may not consider whether additional funding and future multiyear authorizations would address these concerns.

Air Force Colonel Joshua Korzilius, a former National Defense Fellow at CRS, contributed to this product.

Footnotes

1. | Air Force Colonel Joshua Korzilius, a former National Defense Fellow at CRS, contributed to this product.
2. | 10 U.S.C. §§9062(i)(1) and (i)(2)(B).
3. | 10 U.S.C. §9062(i)(2)(A).
4. | See, for example, U.S. Congress, House Committee on Armed Services, Air Force FY2027 Budget Request, hearings, 119th Cong., 2nd sess., May 20, 2026, transcript accessed at https://plus.cq.com/doc/congressionaltranscripts-8466266?4.
5. | Sen. Ted Budd, "Budd, Shaheen lead three-bill package to enhance American airpower and boost defense industrial base," press release, April 22, 2026, https://www.budd.senate.gov/2026/04/22/budd-shaheen-lead-three-bill-package-to-enhance-american-airpower-and-boost-defense-industrial-base/.

6.

Department of the Air Force (DAF), Report to Congressional Committees, Long-Term USAF Fighter Force Structure, August 2025 (hereinafter DAF, Long-Term USAF Fighter Force Structure), was published on the websites of multiple trade publications, including, for example, the Air and Space Forces Association's Air & Space Forces Magazine (see, for example, https://www.airandspaceforces.com/app/uploads/2025/11/USAF-Fighter-Force-Structure-Report_Oct-2025.pdf).

7. | DAF, Long-Term USAF Fighter Force Structure, Figure 3, p. 10.
8. | DAF, Long-Term USAF Fighter Force Structure, Appendix 3, p. 8.

9.

DAF, Long-Term USAF Fighter Force Structure, pp. 9, 10, 16. According to Chairman of the Joint Chiefs of Staff Manual (CJCSM) 3105.01B, Joint Risk Analysis Methodology, December 22, 2023, p. 7, "Risk is the probability and consequence of an event causing harm to a thing that is valued." Risk is assessed within four baseline levels: low, moderate, significant, or heavy.

10. | DAF, Long-Term USAF Fighter Force Structure, pp. 7, 9; White House, National Security Strategy of the United States of America, November 2025; and Department of Defense (DOD), 2026 National Defense Strategy: Restoring Peace Through Strength for a New Golden Age of America, January 23, 2026.
11. | Memorandum for Record from Troy E. Meink, Secretary of the Air Force, "Official Notification of FY26 Fighter PMAI Floor Levels," May 5, 2026, on file with CRS.

12.

Analysts note that the Air Force also changed how it has counted aircraft over time. See Dr. Rebecca Grant, director, Mitchell Institute, et al., "Arsenal of Airpower: USAF Aircraft Inventory 1950-2009," presented at Air Force Association Headquarters, Arlington, VA, November 10, 2010, https://secure.afa.org/Mitchell/presentations/111010TAIStudy_tnx.pdf.

13. | DAF, Office of Statistical Control, Army Air Forces, Statistical Digest, World War II, December 1945, p. 112, https://media.defense.gov/2011/Mar/31/2001330134/-1/-1/0/AFD-110331-045.pdf.

14.

National Museum of the United States Air Force (USAF), "North American P-51D Mustang," fact sheet, https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/196263/north-american-p-51d-mustang/; and National Museum of the USAF, "Lockheed P-38L Lightning," fact sheet, https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/196280/lockheed-p-38l-lightning/.

15. | Mark A. Lorell and Hugh P. Levaux, The Cutting Edge: Half a Century of U.S. Fighter Aircraft R&D, Project Air Force, RAND, 1998, p. 1, https://www.rand.org/pubs/monograph_reports/MR939.html.

16.

DAF, Directorate of Cost & Management Analysis Comptroller of the Air Force, USAF Summary, April 1980, https://media.defense.gov/2011/Apr/04/2001329912/-1/-1/0/AFD-110404-046.pdf; and National Museum of the USAF, "McDonnell Douglas F-4C Phantom II," fact sheet, https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/196051/mcdonnell-douglas-f-4c-phantom-ii/.

17. | Lorell and Levaux, The Cutting Edge: Half a Century of U.S. Fighter Aircraft R&D.

18.

DAF, Assistant Secretary of the Air Force (Financial Management and Comptroller of the Air Force), Deputy Assistant Secretary (Cost and Economics), United States Air Force Statistical Digest, FY1991, https://media.defense.gov/2011/Apr/19/2001330028/-1/-1/0/AFD-110419-007.pdf; and General David W. Allvin, Chief of Staff of the Air Force, The Case for Change: Optimizing for Great Power Competition, DAF, 2023, https://www.af.mil/Portals/1/documents/2024SAF/GPC/The_Case_for_Change.pdf. Multiple U.S. officials, including President George H.W. Bush, used the term peace dividend in the context of a post-Cold War reduction in defense spending. See, for example, President George H.W. Bush, "U.S.-Soviet Nuclear Forces Reduction," C-SPAN video, 24:09, September 27, 1991.

19. | Allvin, The Case for Change.
20. | DAF, Assistant Secretary of the Air Force (Financial Management and Comptroller of the Air Force), Deputy Assistant Secretary (Cost and Economics), United States Air Force Statistical Digest, FY2003.
21. | U.S. Air Force, The Air Force Handbook 2007, p. 10, https://www.govinfo.gov/content/pkg/GOVPUB-D301-PURL-LPS81703/pdf/GOVPUB-D301-PURL-LPS81703.pdf.
22. | CRS Report R48304, F-35 Lightning II: Background and Issues for Congress, by Jennifer DiMascio.
23. | DOD, Fiscal Year 2010 Budget Request: Summary Justification, May 2019, p. 15, https://comptroller.war.gov/Portals/45/Documents/defbudget/fy2010/fy2010_SSJ.pdf#page=22.
24. | Barry Watts, The F-22 Program in Retrospect, Center for Strategic and Budgetary Assessments, August 2009, https://csbaonline.org/resource/the-f-22-program-in-retrospect/.
25. | DAF, Deputy Assistant Secretary (Cost and Economics), Assistant Secretary of the Air Force (Financial Management and Comptroller of the Air Force), United States Air Force Statistical Digest, FY2013, on file with CRS.
26. | Allvin, The Case for Change; CRS Report R47751, The U.S. Defense Industrial Base: Background and Issues for Congress, p. 5; and CRS In Focus IF12257, U.S. Air Force Pilot Training Transformation (PTT).
27. | Justin Bronk, "The Evolution of Russian and Chinese Air Power Threats," Royal United Services Institute, January 8, 2026, https://www.rusi.org/explore-our-research/publications/insights-papers/evolution-russian-and-chinese-air-power-threats.
28. | CJCSM 3105.01B, Joint Risk Analysis Methodology, p. GL-3. According to 10 U.S.C. §9062(h)(3), combat coded means aircraft assigned to meet the primary aircraft authorization for a unit to perform a wartime mission.
29. | Memorandum for Record from Troy E. Meink, Secretary of the Air Force, "Official Notification of FY26 Fighter PMAI Floor Levels," May 5, 2026, on file with CRS.
30. | Congressional Budget Office (CBO), Projected Composition of the U.S. Military's Fleet of Fighter Aircraft Through 2040, July 2026, https://www.cbo.gov/publication/62602.
31. | CBO, Projected Composition of the U.S. Military's Fleet of Fighter Aircraft Through 2040.

32.

Mark A. Gunzinger and Heather R. Penney, Strategic Attack: Maintaining the Air Force's Capacity to Deny Enemy Sanctuaries, vol. 64, Mitchell Institute Policy Paper, February 2026, https://www.mitchellaerospacepower.org/app/uploads/2026/02/Strategic_Attack_Denying_Sanctuary_Policy_Paper_64.pdf#page=21; and Timothy A. Walton and Dan Patt, "Flipping the Script: Redesigning the US Air Force for Decisive Advantage," Hudson Institute, February 17, 2026, https://www.hudson.org/national-security-defense/flipping-script-redesigning-us-air-force-edge-pulsed-resilient-airfields-timothy-walton-dan-patt.

33. | Paul Scharre, "Losing the War of the Future: How New Technologies Threaten America's Military Advantage," Foreign Affairs, July/August 2026, https://www.foreignaffairs.com/united-states/losing-war-future-paul-scharre.

34.

10 U.S.C. §9062(i)(1); DAF Instruction 16-402, Aerospace Vehicle Programming, Assignment, Distribution, Accounting, and Termination, defines Total Aircraft Inventory (TAI) as the sum of Primary Aircraft Inventory (PAI; aircraft assigned to meet the primary aircraft authorization, including PMAI); Backup Aircraft Inventory (BAI; aircraft above the primary inventory to allow for maintenance, modifications, inspection, repairs, or other contingencies without reducing the number of aircraft available for a mission); and Attrition Reserve (AR; aircraft required to replace anticipated losses from accidents or wartime losses). The instruction establishes these categories as required to sustain operational capability (see Figure A2.1 in DAF Instruction 16-402). The text of the instruction describes PMAI as primary mission aerospace vehicle inventory.

35. | 10 U.S.C. §9062(k)(1); and "2025 USAF & USSF Almanac: Equipment, Aircraft Total Active Inventory (TAI)," Air & Space Forces Magazine, June 20, 2025, https://www.airandspaceforces.com/article/2025-usaf-ussf-almanac-equipment/.
36. | 10 U.S.C. §9062(l)(1).
37. | DAF, Long-Term USAF Fighter Force Structure, p. 3.
38. | DAF, Long-Term USAF Fighter Force Structure, p. 4.
39. | CJCSM 3105.01B, Joint Risk Analysis Methodology, p. GL-3.
40. | DAF, Long-Term USAF Fighter Force Structure, p. 9.
41. | DAF, Long-Term USAF Fighter Force Structure, Appendix 3, p. 8.
42. | See footnote 34.
43. | DAF, Long-Term USAF Fighter Force Structure, Appendix 3.
44. | DAF, Long-Term USAF Fighter Force Structure, Figure 4, p. 12.
45. | DAF, Long-Term USAF Fighter Force Structure, Figure 4, p. 12.
46. | DAF, Long-Term USAF Fighter Force Structure, Figure 4, p. 12.

47.

DAF, Long-Term USAF Fighter Force Structure; and General Jeffrey L. Harrigian and Colonel Max M. Marosko III, "Fifth Generation Air Combat: Maintaining the Joint Force Advantage," Transforming Joint Air Power, The Journal of the JAPCC, ed. 24 (July 2017), https://www.japcc.org/articles/fifth-generation-air-combat/.

48. | DAF, Long-Term USAF Fighter Force Structure, p. 7.
49. | U.S. Air Force, "A-10C Thunderbolt II," fact sheet, current as of December 2020, https://www.af.mil/About-Us/Fact-Sheets/Display/Article/104490/a-10c-thunderbolt-ii/.
50. | DAF, Long-Term USAF Fighter Force Structure, p. 3.
51. | Office of the Secretary of the Air Force (@SecAFOfficial), X post, April 20, 2026, https://x.com/SecAFOfficial/status/2046277241613758733?s=20.
52. | Memorandum for Record from Troy E. Meink, Secretary of the Air Force, "Official Notification of FY26 Fighter PMAI Floor Levels," May 5, 2026, on file with CRS.

53.

Fighter aircraft are named according to their basic mission (e.g., F); design number (e.g., 15, 16, 35); and series (e.g., A, B, C, D). Block numbers refer to a production group of identically configured aircraft in a design series. See DAF Instruction 16-401, Army Regulation 70-50, NAVAIRINST 13100.16, Designating and Naming Defense Military Aerospace Vehicles, November 3, 2020, https://static.e-publishing.af.mil/production/1/af_a8/publication/afi16-401/afi16-401.pdf.

54. | U.S. Air Force, "F-15 Eagle," fact sheet, current as of April 2019, https://www.af.mil/About-Us/Fact-Sheets/Display/Article/104501/f-15-eagle/.
55. | Long-Term USAF Fighter Force Structure, p. 3.
56. | Long-Term USAF Fighter Force Structure, p. 3.
57. | Long-Term USAF Fighter Force Structure, p. 4.

58.

U.S. Air Force, Department of Defense Fiscal Year (FY) 2027 Budget Estimates, Air Force, Justification Book Volume 1 of 2, Aircraft Procurement, Air Force, April 2026, p. 33, https://www.af.mil/Portals/1/documents/Secretariat%20of%20the%20AF/SAF-FM/Budget%20-%202027/Budget%20docs/FY27%20Air%20Force%20Aircraft%20Procurement%20Volume%20I.pdf?ver=4kiKWbFkcqsD4dDrO7-P4g%3d%3d#page=69.

59. | U.S. Air Force, "F-16 Fighting Falcon," fact sheet, current as of September 2021, https://www.af.mil/About-Us/Fact-Sheets/Display/Article/104505/f-16-fighting-falcon/.

60.

DAF, Long-Term USAF Fighter Force Structure, p. 4. According to the report, post-block modernization includes F-16 Block 40 and Block 50 aircraft. On p. 2, the report stated, "legacy capability fighter aircraft" includes pre- and post-block F-16s, F-15C/D F-15E/EX and A-10 aircraft. On p. 4, the report said, post-block modernization includes F-16 Block 40 and Block 50 aircraft. Other entities may define post-block modernization as including only F-15EX and F-35 fighters.

61. | Lockheed Martin, "F-16 Block 70/72: The World's Most Advanced 4th Generation Fighter," 2020, https://www.lockheedmartin.com/content/dam/lockheed-martin/aero/documents/F-16/Jan20_Product%20Card%20F-16%20Block%207072%20media.pdf.
62. | DAF, Report to Congressional Committees, Sustainment and Recapitalization of Air Force National Guard Fighter Fleet, April 2025, p. 13.
63. | CRS Report R48304, F-35 Lightning II: Background and Issues for Congress, by Jennifer DiMascio.
64. | DAF, Long-Term USAF Fighter Force Structure, p. 4.
65. | DAF, Long-Term USAF Fighter Force Structure, p. 4.
66. | U.S. Air Force, Department of the Air Force Budget Overview, Fiscal Year 2027, April 2027, p. 13, https://www.af.mil/Portals/1/documents/Secretariat%20of%20the%20AF/SAF-FM/Budget%20-%202027/Supporting%20Docs/FY27%20Budget%20Overview.pdf?ver=7hl86QkYQPIRHTJhhh4jHg%3d%3d.
67. | U.S. Air Force, Department of Defense Fiscal Year (FY) 2027 Budget Estimates, Air Force, Justification Book Volume 1 of 2, Aircraft Procurement, Air Force, April 2026, p. 9.
68. | DAF, Long-Term USAF Fighter Force Structure, p. 4; and CRS In Focus IF12740, U.S. Air Force Collaborative Combat Aircraft (CCA), by Jennifer DiMascio.
69. | DAF, Long-Term USAF Fighter Force Structure, p. 4.
70. | U.S. Air Force, Department of Defense Fiscal Year (FY) 2027 Budget Estimates, Air Force, Justification Book Volume 2 of 2, Research, Development, Test, and Evaluation (RDT&E), Air Force, April 2026, p. 887, https://www.af.mil/LinkClick.aspx?fileticket=pEQ0rdRJvBs%3d&portalid=1#page=471#page=937.
71. | DAF, Long-Term USAF Fighter Force Structure, p. 14.
72. | CRS In Focus IF12805, U.S. Air Force Next-Generation Air Dominance (NGAD) Fighter, by Jennifer DiMascio.
73. | U.S. Air Force, Department of Defense Fiscal Year (FY) 2027 Budget Estimates, Air Force, Justification Book Volume 2 of 2, RDT&E, Air Force, p. 421.
74. | Colonel Jose Gutierrez Del Arroyo, "Adoption of the JSE Digital Test and Training Ranges," Defense Acquisition University Magazine, July-August 2024, https://www.dau.edu/library/damag/july-aug2024/adoption-jse-digital-test.
75. | DAF, Long-Term USAF Fighter Force Structure, p. 14.
76. | U.S. Air Force, Department of Defense Fiscal Year (FY) 2027 Budget Estimates, Air Force, Justification Book Volume 2 of 2, RDT&E, Air Force, p.473.
77. | DAF, Long-Term USAF Fighter Force Structure, p. 4.
78. | DAF, Long-Term USAF Fighter Force Structure, p. 11.
79. | DAF, Long-Term USAF Fighter Force Structure, p. 11.
80. | DAF, Long-Term USAF Fighter Force Structure, p. 9.
81. | DAF, Long-Term USAF Fighter Force Structure, p. 9; and CRS Report R48304, F-35 Lightning II: Background and Issues for Congress, by Jennifer DiMascio.
82. | DAF, Long-Term USAF Fighter Force Structure, p 7.
83. | DAF, Long-Term USAF Fighter Force Structure, p. 9.
84. | DAF, Long-Term USAF Fighter Force Structure, p. 8.
85. | Lockheed Martin, "F-35 Breaks Delivery Record, Continues Combat Success in 2025," press release, January 7, 2026, https://www.f35.com/f35/news-and-features/F35_Breaks_Delivery_Record_Continues_Combat_Success_in_2025.html.
86. | CRS correspondence with Air Force Legislative Liaison, April 4, 2026.

87.

According to 10 U.S.C. §117, DOD has established the Defense Reporting Readiness System, which rates mission capability. In addition, 10 U.S.C. §482 requires DOD to report a Semi-annual Readiness Report to Congress at least 30 days after the second and fourth quarter of the calendar year. See CRS In Focus IF12240, Military Readiness: DOD Assessment and Reporting Requirements; and DOD Instruction 7730.66, Readiness Reporting Guidance for the Defense Readiness Reporting System, December 10, 2024, https://www.esd.whs.mil/Portals/54/Documents/DD/issuances/dodi/773066p.pdf.

88. | DAF, Long-Term USAF Fighter Force Structure, p. 12.
89. | DAF, Long-Term USAF Fighter Force Structure, p. 12.
90. | DAF, Budget Overview: Fiscal Year 2027, April 2027, p. 45, https://www.af.mil/Portals/1/documents/Secretariat%20of%20the%20AF/SAF-FM/Budget%20-%202027/Supporting%20Docs/FY27%20Budget%20Overview.pdf?ver=7hl86QkYQPIRHTJhhh4jHg%3d%3d#page=45.
91. | The Flying Hour Program is a model for determining requirements for pilot flying hours. See Air Force Instruction 11-102, Flying Hour Program Management, Flying Operations, December 8, 2020, https://static.e-publishing.af.mil/production/1/af_a3/publication/afi11-102/afi11-102.pdf.
92. | DAF, Long-Term USAF Fighter Force Structure, p. 12.

93.

Presentation by General James C. Slife, Vice Chief of Staff of the Air Force, in U.S. Senate, Senate Committee on Armed Services, Subcommittee on Readiness, The Fiscal Year 2025 U.S. Air Force Budget Request for Readiness, April 17, 2024, https://www.armed-services.senate.gov/imo/media/doc/slife_statement.pdf.

94.

U.S. Air Force, Air Education and Training Command (AETC) Public Affairs, "Boosting readiness: AETC's plan to train 1,500 pilots annually," press release, June 4, 2025, https://www.aetc.af.mil/News/Article-Display/Article/4205462/boosting-readiness-aetcs-plan-to-train-1500-pilots-annually/; and U.S. Congress, House Armed Services Committee, Streamlining Procurement for Effective Execution and Delivery and National Defense Authorization Act for Fiscal Year 2026, report to accompany H.R. 3838, 119th Cong., 1st sess., H.Rept. 119-231, August 19, 2025.

95. | DAF, Long-Term USAF Fighter Force Structure, p. 6.
96. | DAF, Long-Term USAF Fighter Force Structure, p. 6.
97. | DAF, Long-Term USAF Fighter Force Structure, pp. 12-13.
98. | DAF, Long-Term USAF Fighter Force Structure, pp. 18-19.
99. | DAF, Long-Term USAF Fighter Force Structure, p. 10.
100. | National Guard Association of the United States, "ANG Fighter Recapitalization, Air National Guard: Fiscal Year 2026 Requirements for the Air National Guard," fact sheet, https://www.ngaus.org/sites/default/files/2025-06/ANG%20Fighter%20Recapitalization%20Fact%20Sheet%20FY26.pdf.

101.

Testimony of General Steven S. Nordhaus, Chief, National Guard Bureau, in U.S. Congress, Senate Committee of Appropriations, Subcommittee on Defense, National Guard Posture Statement for Fiscal Year 2026, hearing, 119th Cong., 1st sess., May 22, 2025, https://www.appropriations.senate.gov/imo/media/doc/General%20Steven%20S.%20Nordhaus%20Testimony.pdf.

102. | H.R. 8800, §141.
103. | H.R. 8800, §141.
104. | S. 4784, §131.
105. | S. 4784, §131.
106. | John A. Tirpak, "Air Force's New Fighter Math Doesn't Add Up for Critics," Air & Space Forces Magazine, November 13, 2025, https://www.airandspaceforces.com/air-force-fighters-force-structure-manning-readiness-issues/.

107.

Lauren Edson and Phillip C. Saunders, "Rightsizing the PLA Air Force: Revisiting an Analytic Framework," Joint Force Quarterly, vol. 118, 3rd quarter (July 15, 2025), https://ndupress.ndu.edu/Media/News/News-Article-View/Article/4244397/rightsizing-the-pla-air-force-revisiting-an-analytic-framework/.

108. | Tirpak, "Air Force's New Fighter Math Doesn't Add Up for Critics."
109. | Scharre, "Losing the War of the Future: How New Technologies Threaten America's Military Advantage."
110. | Secretary of the Air Force Public Affairs, "Air Force shapes requirements for a new era of uncrewed airpower," press release, July 9, 2026, https://www.af.mil/News/Article-Display/Article/4539232/air-force-shapes-requirements-for-a-new-era-of-uncrewed-airpower/.
111. | DAF, Long-Term USAF Fighter Force Structure.

112.

Retired Colonel John Venable with Joshua Baker, Winning the Next War: Overcoming the U.S. Air Force's Capacity, Capability, and Readiness Crisis, Mitchel Institute for Aerospace Studies, Air Forces Association, September 2025, pp. 39, 51, https://www.mitchellaerospacepower.org/app/uploads/2025/09/Winning-the-Next-War-Capability-Capacity-Readiness-FINAL.pdf.

113. | U.S. Air Force, Department of Defense Fiscal Year (FY) 2027 Budget Estimates, Air Force, Justification Book Volume 1 of 2, Aircraft Procurement, Air Force, April 2026, p. 46.
114. | H.R. 8800, §§161-162; S. 4784, §§132-133. For more information about multiyear procurement authority, see CRS Report R41909, Multiyear Procurement (MYP) and Block Buy Contracting in Defense Acquisition: Background and Issues for Congress.
115. | DAF, Long-Term USAF Fighter Force Structure, p. 7.

116.

U.S. Congress, Senate Committee on Armed Services, Hearing to consider the nomination of Gen David W. Allvin, USAF for reappointment to the grade of general and to be Chief of Staff of the Air Force, stenographic transcript, 118th Cong., 1st sess., September 12, 2023, https://www.armed-services.senate.gov/imo/media/doc/transcript_23-63_____09-12-2023.pdf.

117.

Greg Hadley, "USAF Wants to Dump Old Fighters. Congress Isn't So Sure," Air & Space Forces Magazine, June 21, 2023, https://www.airandspaceforces.com/lawmakers-air-force-plans-retire-aging-fighters/; and Rep. Austin Scott, "Rep. Austin Scott on HASC Passage of FY26 NDAA," press release, July 16, 2025, https://austinscott.house.gov/2025/7/rep-austin-scott-on-hasc-passage-of-fy26-ndaa.

118. | 10 U.S.C. §9062.
119. | P.L. 119-60, §147.
120. | H.R. 8800, §142.
121. | U.S. Government Accountability Office (GAO), Tactical Aircraft: Operation and Maintenance Spending Varies by System, and Availability Generally Does Not Meet Service Goals, GAO-25-107870, October 21, 2024, https://www.gao.gov/products/gao-25-107870.
122. | John A. Tirpak, "Air Force Mission Capability Rates Reach Lowest Levels in Years," Air & Space Forces Magazine, February 18, 2025, https://www.airandspaceforces.com/air-force-mission-capable-rates-fiscal-2024/.
123. | Sen. Ted Budd, "Budd, Shaheen lead three-bill package to enhance American airpower and boost defense industrial base," press release, https://www.budd.senate.gov/2026/04/22/budd-shaheen-lead-three-bill-package-to-enhance-american-airpower-and-boost-defense-industrial-base/.
124. | Stephen Losey, "US Air Force eyes inspections, spare parts funding to boost readiness," Defense News, February 2, 2026, https://www.defensenews.com/air/2026/02/02/us-air-force-eyes-inspections-spare-parts-funding-to-boost-readiness.
125. | Brooke Weddle et al., "Accelerating progress: Maximizing the return on talent in A&D," in 2025 AIA Aerospace and Defense Workforce Study, June 2025, https://www.mckinsey.com/industries/aerospace-and-defense/our-insights/accelerating-progress-maximizing-the-return-on-talent-in-a-and-d.

126.

Letter from Major Gen. David K. Pritchett, Alabama National Guard Adjutant General et al., to Sen. Susan Collins, Chairwoman, Committee on Appropriations et al., April 1, 2026, https://www.ngaus.org/sites/default/files/2026-04/ANG%20Fighter%20Aircraft%20States_Appropriations%20Committee_TAG%20Letter_FINAL.pdf.

127. | H.R. 8800, §1099C.