Air Force Needs 72 Fighters Yearly, but Budget Funds 45 and Factories Cannot Deliver

Seventy-two new fighters a year is the rate the U.S. Air Force says it needs to keep its fleet from shrinking. Its current budget funds 45 24 F-35As and 21 F-15EXs leaving a 27-aircraft gap before production constraints are even considered.

The service has now acknowledged that industry could not immediately supply the missing aircraft if more money became available. In early June 2026, Air Force Vice Chief of Staff Gen. John Lamontagne said demand was exceeding contractor output. No bill can legislate a factory into producing faster than its current capacity allows, he said. The Air Force separately described the 72-fighter objective as “not currently achievable.” Details of the 45-aircraft budget request show how procurement has been divided between the two active fighter lines.

The gap is wider than an assembly-line problem

Final assembly is only one limit. A completed fighter depends on engines, avionics hardware, tested software and thousands of components arriving in the correct sequence. A late item can leave an aircraft physically built but not ready for delivery.

The F-35’s Technology Refresh 3 package illustrates that distinction. The new computing hardware and software underpin the broader Block 4 modernization. Technology Refresh 3 was originally due in April 2023, but the schedule cited for the completed package moved into 2026. During the delay, Lockheed Martin accumulated more than 100 aircraft that could not be delivered with the required configuration.

That backlog matters because production and delivery are not interchangeable measures. Lockheed delivered 191 F-35s across customers in 2025, but a high annual output does not erase integration work deferred on earlier aircraft. Each jet still has to reach an accepted hardware and software standard, and unresolved modernization work consumes engineering, test and modification capacity that could otherwise support a cleaner production flow.

Parts availability adds another layer. At the beginning of 2025, Lockheed was reportedly awaiting more than 4,000 parts and components needed for F-35 production. About 1,600 were associated with the Technology Refresh 3 and Block 4 upgrades. Those figures indicate that the constraint was distributed across the production system rather than concentrated in one easily expanded workstation.

Late engines constrain completed aircraft

Propulsion schedules have created a separate bottleneck. All 123 Pratt & Whitney F135 engines delivered in 2024 were late, with an average delay of 238 days. The Government Accountability Office characterized delayed engine deliveries as a “significant risk to operational readiness.” Contracts covering engines for production Lots 18 and 19 were also expected to be finalized in spring 2026, six months later than planned.

An aircraft manufacturer cannot compensate for that kind of delay simply by accelerating airframe work. Engines are major, serialized systems with their own suppliers, inspections and acceptance requirements. Increasing funded aircraft quantities without synchronized propulsion and component output can therefore expand work in progress rather than produce an equal increase in deliverable jets.

The F-15EX provides capacity, but not an instant fix

The Air Force is using Boeing’s F-15EX as a second new-build fighter line while F-35 modernization continues and future aircraft remain in development. The F-15EX adds modern avionics and fly-by-wire controls to the established F-15 design, and the planned fleet had increased to 267 aircraft by mid-2026.

Even that line has finite capacity. Boeing was expected to reach 24 F-15EXs annually, while expansion to as many as 36 would require additional funding for facilities. Long-term contracts can give manufacturers a steadier demand signal for tooling, supplier orders and hiring, but a contract ceiling or larger appropriation does not itself create trained machinists, qualified engineers or added assembly space.

Those workers and suppliers are also being sought by other major programs, including the F-35, B-21 bomber, T-7A trainer, Sentinel missile and classified projects. The same workforce pressure affected future-fighter planning: defense officials said the industrial base had enough qualified engineering capacity to move quickly on only one of the Air Force’s F-47 and Navy’s F/A-XX programs at a time.

The result is a procurement problem with four linked limits: appropriated aircraft quantities, avionics integration, engines and components, and skilled industrial capacity. The Air Force expects its fighter fleet to keep shrinking through at least 2028 before stabilizing if its plan proceeds as anticipated. Closing the 27-aircraft annual gap will require those production systems to rise together; funding more airframes without matching engines, parts and labor would leave the 72-fighter objective on paper.

By David Whitaker — Associate editor for AMI’s aerospace and drone systems desk, translating flight systems, aircraft programs, spaceflight, and UAV developments into accessible technical stories.