AURORA, Colo. — Barely more than six in 10 aircraft in the Air Force’s fleet were able to carry out their missions on an average day in fiscal 2024, according to a Defense News analysis.
The fleet-wide mission capable rate of 62% is the lowest in recent memory. It comes as the Air Force’s arsenal of more than 5,000 planes is aging and the service finds it increasingly difficult to keep some in the air.
The Air Force provided statistics on how many of each kind of aircraft it had in 2024, as well as the percentage of time each aircraft was ready to carry out its mission. Those stats were first reported by Air and Space Forces Magazine.
To come up with a fleet-wide mission-capable rate, Defense News calculated a weighted average of all airframes. Using a weighted average places more emphasis on airframes that the service has more of — such as the C-17 Globemaster, F-16 Fighting Falcon and the F-35A Joint Strike Fighter — and less emphasis on rarer airframes.
With the Air Force’s fleet at 5,025 — the smallest in the service’s 78-year history — a 62% mission-capable rate equates to roughly 1,900 planes being out of commission at any given time.
Heather Penney, a former F-16 pilot and senior resident fellow at the Mitchell Institute for Aerospace Studies, said the figures are concerning, and suggest the situation is likely getting even worse this year.
“Readiness is often a lagging indicator,” Penney said. “And those aren’t even today’s MC rates,” which she predicted will be even worse when 2025 is done.
The Air Force, along with other services, has for years struggled to pull up its mission-capable rates. President Donald Trump’s first defense secretary, Jim Mattis, in 2018 set an ambitious goal of 80% readiness for F-16s, F-22s and F-35s — which went unmet.
And judging by a similar metric — aircraft availability — the true state of the fleet may even be worse.
According to a 2019 paper by analysts at the Air Force Institute of Technology and Air Force Materiel Command, mission-capable rates do not consider aircraft that are awaiting depot maintenance or are otherwise not possessed at the unit level. Those analysts said aircraft availability rates are a truer measure of how the Air Force’s planes are doing.
In his Monday keynote address to the Air and Space Force Association’s AFA Warfare Symposium in Aurora, Colorado, Air Force Chief of Staff Gen. David Allvin used that aircraft availability statistic to sound perhaps the strongest alarm yet about the state of the service’s fleet.
Allvin displayed a chart showing the increasing trouble facing the Air Force’s planes. The chart tracked a steady growth of the average aircraft age in the fleet — from about 17 in 1994 to nearly 32 in 2024 — while aircraft availability plummeted from 73% to 54%.
Allvin praised the service’s maintainers, who work long hours in tough conditions to keep their planes flying.
“You wouldn’t know this on the front lines,” Allvin said of the growing availability problems, “because of the miracles that are going on from our maintainers and those who are sustaining [airplanes]. … We’re eating into whatever margin we had.”
Trump and Defense Secretary Pete Hegseth have proclaimed a focus on improving the military’s “lethality,” firing top brass they perceive to be standing in the way. Fresh budget cuts to the Defense Department have had the services clamoring to be spared from measures that would bring down readiness rates further.
In this environment, Penney said, poor aircraft readiness rates make top Air Force leaders vulnerable.
Even more worrying to Penney is that there’s no simple way to turn the situation around.
“It’s complex, because it’s spares, maintenance manpower, maintenance experience levels [and] depots, which are so behind right now,” Penney said.
‘Tired iron,’ even more exhausted
The Air Force’s current predicament, as Penney sees it, is largely due to the lack of enough major aircraft modernizations. Much of the Air Force’s fleet was around during the Cold War, and there are several air frames — such as the B-52 Stratofortress, C-5 Galaxy and KC-135 Stratotanker — that were around during the Vietnam War.
Air Force officials commonly refer to such planes as “tired iron,” and quip that they “find new and interesting ways to break.” Without enough modernizations to replace those planes with new airframes, the service is forced to sustain them longer and longer, trying to scrounge up spare parts to fix them.
In the case of the Air Force’s 76 B-52Hs, which have been flying since the early 1960s, some companies that originally made spare parts are no longer in business. This often forces the service to find new sources for those parts, custom make the parts itself, or “cannibalize” parts from other Stratofortresses that are even more broken.
The situation results in a slow and steady decline in the B-52′s availability. In 2021, the bomber had a 59% mission-capable rate, but that has now slid to 54%.
The overall numbers show a swift decline in aircraft readiness over the last few years, driven by some of the service’s most crucial airframes, such as the F-35A.
The Air Force’s overall mission-capable rate was nearly 78% in 2012, but steadily slid as the decade progressed to a then-low of slightly below 70% in 2018. Two years later, that fleet-wide figure had risen to 72.7%, and then dropped to 71.5% in 2021.
The Lockheed Martin-made F-35A — the cornerstone of the service’s fighter fleet and one of the most expensive military programs in history — has been plagued with reliability and availability issues. In 2021, the fighter was available nearly 69% of the time, according to the Air Force.
But the F-35A’s mission capable rates have since plunged, and the jet was ready 51.5% of the time in 2024.
The Joint Strike Fighter’s lagging availability has become such a problem that its program executive officer, Lt. Gen. Michael Schmidt, in 2023 announced a “war on readiness” that seeks to improve how often the F-35 can fly.
The Government Accountability Office in 2023 released a report on the entire F-35 fleet’s maintenance challenges, which said services lacked spare parts and technical data needed to repair the fighters. Maintainers were also not properly trained, GAO said, and an effort to expand repair depots was falling behind.
Chauncey McIntosh, a Lockheed vice president and general manager of the company’s F-35 program, said in an interview at AFA that he is focused on improving the jet’s mission readiness, and is working with the F-35 Joint Program Office to do so.
Most parts in the F-35 are lasting longer than expected, McIntosh said, and the company is focused on improving those parts that are less reliable, which the program refers to as “degraders.”
“We’ve been able to drive down those top degraders, and there’s only really a few left that we’re focused on now,” McIntosh said.
The next major issue to tackle, he said, will be to ensure that repair depots have all the spare parts they need to fix F-35s.
“As we get the right parts, and get the right [funding from Congress for them], then we’ll be able to go procure those parts, put those parts on the shelf,” McIntosh said. “This is a growing fleet, so we need to make sure that the [spare parts inventory] keeps up with the fleet size — for not only the U.S., but all of our international partners.”
Readiness drops across the fleet
Other key airframes that dropped precipitously in recent years include the A-10 Warthog, the CV-22 Osprey, the F-16 fighter, the KC-46 Pegasus tanker and the T-38C Talon jet trainer.
Mission-capable rates for the Air Force’s Ospreys were at about 51% in 2021, but by 2023 plunged to 46% and then to 30% in 2024. The Osprey, which is also flown by the Navy and Marine Corps, has been plagued in recent years by faulty components, clutch problems and fatal crashes that led to multiple groundings.The A-10 Warthog’s readiness rate slid from 72% in 2021 to 67% in 2023 and 2024.The F-16C fell from almost 72% in 2021 down to 64% in 2024; while the two-seater variant, the F-16D, dropped even more precipitously during that time, from 69% to 59%.The KC-46′s mission capable rates dropped from 71% in 2021 to 61% in 2024.The T-38C’s availability also declined from 63% in 2021 to 55% in 2024. The Air Force is buying new T-7A Red Hawk trainers from Boeing to replace the nearly 60-year-old T-38. But the T-7 has repeatedly fallen behind schedule, which will require the Air Force to keep flying — and maintaining — T-38s years longer than originally expected.
The lack of enough mission-capable aircraft has forced the Air Force to make tough choices on how to use its working planes. The service has for years prioritized its ability to carry out operational missions over other missions like training. This means it front-loads its working aircraft to units overseas or that otherwise carry out operations, but stateside units are more likely to have shortages of working aircraft.
U.S. Air Forces Central Command, which for decades has flown aircraft such as the A-10, F-15, F-16 and F-35 in the Middle East to project American airpower, is one example of a command that is prioritized in such a way.
But even getting to the head of the line for things like spare parts doesn’t automatically solve all of AFCENT’s problems, commander Lt. Gen. Derek France told reporters at AFA. Sometimes logistical hurdles mean spare parts still take a while to get to the deployed jets that need them, he said. And environmental factors such as heat and sand — particularly in summertime — can wear on the aircraft, France said.
And most of all, he said, AFCENT’s planes are growing old, just like the rest of the service’s aircraft.
“The fact of the matter is, we’ve got an aging fleet,” France said. “Our AFCENT airmen do heroic work in keeping them in the air. The things that I have seen, with our airmen, to be able to put together the parts, and get after the things they need to, has been impressive in our [area of responsibility], for sure.”
France could not quantify readiness rates for AFCENT planes, but said “our airmen meet mission when they need to.”
A critical part of being AFCENT commander, he said, is forecasting when his units will need to surge aircraft and put large numbers of jets in the air, and when they can pull back. Those “pull back” phases give maintainers time and space to work more intensely on AFCENT’s planes and “get our jets healthy again,” France said.
In his speech at AFA, Allvin stressed how important it is for the Air Force to fix this problem once and for all.
“Our Air Force continues to be the most dominant on the planet,” Allvin said. “I don’t want to be here next year, or have the next chief, say we’re no longer [dominant]. So we’ve got to work on this.”
Stephen Losey is the air warfare reporter for Defense News. He previously covered leadership and personnel issues at Air Force Times, and the Pentagon, special operations and air warfare at Military.com. He has traveled to the Middle East to cover U.S. Air Force operations.
