Despite record budgets, American fighter jet availability is declining—a vulnerability that has become critical amid prolonged operations against Iran.
Summary
American airpower rests upon a massive fleet, but an increasing share of that fleet is not immediately mission-ready. The latest detailed data released by the US Air Force shows that in 2024, the average “mission capable” rate across its aircraft dropped to 67.15%, its lowest level in at least a decade. The situation was even more concerning for several fighter types: 40% for the F-22, approximately 52% for the F-35A, and 55% for the F-15E. These figures do not mean that half of all American jets are incapable of combat. Rather, they reveal growing strain caused by aging airframes, spare parts shortages, heavy maintenance backlogs, and technician availability. The American campaign against Iran in 2026 illustrates the concrete consequences: engaged units can receive prioritized resources, but only at the cost of immense pressure on rotations, spare parts stockpiles, and non-deployed units back home.
American Fighter Availability Has Been Eroding for Several Years
The US defense budget is not enough to keep all aircraft mission-ready simultaneously. In October 2024, the Government Accountability Office found that the mission-capable rate of all studied tactical aircraft across the US Air Force had decreased between 2018 and 2023, even as operating and support spending remained substantial. US forces spent $57.2 billion on tactical aircraft sustainment between 2018 and 2023 across all military branches.
The latest complete data series published by the USAF covers Fiscal Year 2024. The average mission-capable rate across all its fleets fell to 67.15%, down from 69.92% in 2023 and 71.24% in 2022. For fighter jets alone, the average hovered near 60%.
Disparities between aircraft types were significant. The F-16C reached roughly 64%, the F-15E stood at 55%, the F-35A at 51.5%, and the F-22A at just 40.19%. The F-15EX exceeded 83%, but the fleet comprised only eight aircraft at the time.
The case of the Lockheed Martin F-22 Raptor is particularly telling. Its rate was still 57.4% in 2022.
F-22 Raptor: https://www.flyajetfighter.com/planepedia/lockheed-martin-f-22-raptor/
The Difference Between a Mission-Capable Aircraft and a Fully Operational One Is Essential
These statistics must be interpreted correctly. An aircraft is classified as “mission capable” if it can perform at least one of its assigned missions. It may therefore be available for an air-to-air mission while remaining temporarily incapable of executing certain strike, electronic warfare, or reconnaissance missions.
The “fully mission capable” tier is far more demanding. It signifies that the aircraft can perform all of its intended mission sets.
The US Air Force no longer routinely publishes detailed data for each fleet. It also ceased public reporting of traditional rates by type after 2024, opting instead for new metrics designed to better gauge an individual unit’s real-world capacity to generate required airpower. Comparing figures across different periods has consequently become complex.
The F-35 nonetheless illustrates the scale of the issue. According to the GAO, across the entire US F-35 fleet spanning all three service branches, the mission-capable rate fell from 67% in 2021 to 44% in 2025. The fully mission capable rate dropped from 38% to just 25%. While these figures do not apply exclusively to USAF F-35As, they underscore the broader sustainment challenges facing the program.
F-35 Lightning II: https://www.flyajetfighter.com/planepedia/f-35-lightning-ii/
Aging Airframes Turn Every Flight Hour into an Industrial Challenge
The USAF continues to operate nearly 2,000 fighter and attack aircraft. As of September 30, 2025, its inventory included 826 F-16s, 217 F-15Es, 184 F-22As, and 500 F-35As. The average age of the combat fleet exceeded 25 years.
The F-16 perfectly illustrates this phenomenon. Some airframes are more than 30 years old. Officials from an Air National Guard unit explained in 2026 that an F-16 originally required roughly six to eight maintenance hours per flight hour. Their unit was now devoting between 15 and 20 maintenance hours to that same single flight hour. Structural fatigue cracks and other age-related issues are appearing with increasing frequency.
F-16 Fighting Falcon: https://www.flyajetfighter.com/planepedia/f-16-fighting-falcon/
The consequence is mechanical: the more maintenance an aircraft requires, the more technicians, parts, and time are needed to generate an additional sortie.
Maintenance Depots Have Become a Major Bottleneck
The bottleneck is not confined to front-line squadrons.
In May 2026, the GAO published a critical analysis of the USAF’s three main Air Logistics Complexes. Measured against originally scheduled timelines, 73% of aircraft undergoing depot-level maintenance in 2024 were delayed, compared to 31% in 2019.
Airframe aging reveals unexpected defects during inspections, including corrosion, fatigue cracks, worn components, or additional mandatory modifications. Technicians must then source parts, request specialized engineering assessments, or even manufacture components that are no longer in production.
The GAO also pointed to severe staffing shortages in key technical fields. At the Ogden Air Logistics Complex—which handles F-16 and F-35 maintenance—industrial engineering positions were only 60% filled in 2024.
Increasing budget allocations does not instantly solve the problem. Money cannot manufacture an obsolete part overnight, nor can it immediately transform a new recruit into an experienced master technician.
The F-35 Shows That Modernity Does Not Guarantee High Availability
The F-35 was intended to resolve issues associated with aging legacy fleets. Instead, it introduced new ones.
The GAO highlights parts shortages, reliability concerns, corrosion inspection burdens, restricted access to proprietary technical data, and heavy reliance on defense contractors. In response, the Joint Program Office launched a new sustainment strategy calling for an additional $13.7 billion through 2031, with industry required to supply over $7 billion in additional equipment and spare parts.
The paradox is striking: the F-35 is one of the most advanced combat aircraft in the world, yet an unavailable sensor, component, or maintenance procedure can ground an airframe worth over $80 million.
The War Against Iran Transforms an Accounting Issue into a Military Constraint
By September 2026, conflict with Iran is no longer a hypothetical scenario for the USAF. Operational commitments in 2026 have subjected the fleet to a tempo rarely seen in recent decades.
During the primary phase of Operation Epic Fury, approximately 500 combat aircraft generated nearly 250 sorties per day. According to the Chief of Staff of the Air Force, roughly 10,000 sorties were flown in 38 days against more than 13,000 targets.
However, this campaign highlights an essential nuance regarding low overall readiness statistics: a fleet with an annual average mission-capable rate of 50% or 60% does not necessarily go to war with only half its strength.
The USAF concentrates spare parts, technicians, and logistical assets onto forward-deployed units. During Epic Fury, engaged F-35s demonstrated significantly higher availability rates once their support chain was prioritized. An Air Combat Command official noted in September 2026 that the experience proved what the platform could deliver when supplied with necessary resources.
Yet this strategy shifts the burden rather than removing it.
Prolonged Campaigns Progressively Drain the Unit Rotation System
A short air campaign lasting a few days can be sustained by channeling top-tier aircraft, spare parts, and technicians to key bases. A monthslong campaign demands a far different approach.
By September 2026, fresh F-16 and F-35 squadrons were deploying to the Middle East to relieve units that had surpassed standard rotation cycles. The Vermont Air National Guard’s 158th Fighter Wing, for example, concluded a deployment cycle spanning nearly nine months that included consecutive operations across multiple theaters.
Every extension incurs operational debt. Aircraft accumulate flight hours rapidly, inspection intervals arrive faster, engine service lives are consumed, and maintenance personnel work extended shifts. Units returning home must then rebuild their spare parts inventories and restart their training cycles.
During Epic Fury, the USAF even moved certain heavy maintenance capabilities closer to the European theater to avoid routinely flying aircraft requiring major repairs all the way back to the United States.
The True Vulnerability Appears When Multiple Crises Occur Simultaneously
The central question is not whether the United States can surge several hundred combat aircraft for a single major campaign—it has just demonstrated that it can.
The real question is how long it can sustain that effort, and then repeat it elsewhere.
An air force must simultaneously cover the Middle East, Europe, the Indo-Pacific, homeland defense, and pilot training. A squadron engaged against Iran is not simultaneously available for a prolonged deployment in the Pacific. A spare part dispatched on priority to an operational unit cannot equip a training aircraft in the United States.
Availability thus becomes a strategic dilemma rather than a purely technical one. The United States maintains unmatched airpower in terms of overall volume, capability, and logistics infrastructure. Yet the operational depth of that power is less forgiving than total aircraft inventories suggest.
The ultimate test for the USAF will likely not be its ability to launch the initial wave of a major operation, but its capacity to sustain the hundredth—while retaining enough mission-ready aircraft, spare parts, and personnel to handle the next crisis.