As the US Air Force fleet keeps shrinking, can it still win wars?

In February 2017, then-Air Force Chief of Staff Gen. Dave Goldfein issued a warning.

Speaking at the Center for Strategic and International Studies in Washington, Goldfein rattled off all the missions the Air Force must undertake: defending the U.S. against attack, operating two legs of the nation’s nuclear triad, projecting air power around the globe and, at the time, defeating the militant group known as the Islamic State.

“Every one of those missions is a growth area,” Goldfein said. “And while these missions have been growing, our Air Force has been getting smaller. … We’re actually the smallest Air Force we’ve ever been.”

At the time, the service had about 5,500 aircraft in its inventory. Since then, it has shrunk further and is now on track to get smaller still.

The Air Force expects its fleet of fighters, bombers, tankers, cargo planes, drones and other aircraft to dip below 5,000 in fiscal 2025, as retirements of older, worn down and outdated airframes outpace procurement of their replacements. Indeed, the fleet could drop to 4,903 total aircraft next year, but it may yet fall further.

“Right now, the Air Force is as big as it will be,” Maj. Gen. Dave Tabor, director of programs for the service’s Office of the Deputy Chief of Staff for Plans and Programs, said in a March 21 interview. “In light of the budget uncertainties, it’s really difficult to predict exactly what size [the fleet] will be, next year or five years from now.”

The fleet already totals less than one-fifth of its size during its fiscal 1956 peak, when the service had 26,104 aircraft, according to the Mitchell Institute for Aerospace Studies. During that period, the number of F-84 Thunderjet and F-86 Sabre fighters alone exceeded 6,400, far greater than the Air Force’s entire combined fleet of 5,032 airframes in fiscal 2024.

The workforce is smaller as well. The Air Force in fiscal 2025 aims to fall to 320,000 active duty jobs, dropping by about 13,000 billets over the previous five fiscal years. The roles of those airmen are shifting, too, as the service tries to bolster non-flying missions like cyber offense and defense that are key to modern warfare.

The Air Force’s fleet is now 52% bigger than the Navy and Marine Corps’ combined inventory of 3,308 aircraft.

The current Air Force chief of staff, Gen. David Allvin, and other top service officials point to exponential increases in capability among the remaining aircraft — such as striking targets with firepower and precision far beyond that of previous generations — to assuage concerns over the declining number of aircraft.

But the shrinking fleet worries some lawmakers and observers.

Todd Harrison, a defense analyst at the American Enterprise Institute think tank, said that while modern aircraft do offer more speed, range, stealth and other advantages over previous generations of technology, “the reality is that one plane can only be in one place at a time.”

“For the credibility of our deterrence and our force posture, size still matters,” Harrison told Defense News. “That’s where we’re coming up short.”

“An F-35 deployed over in the Indo-Pacific region is not doing anything to help you in [Europe],” he added.

Heather Penney, a former F-16 pilot and senior resident fellow at the Mitchell Institute for Aerospace Studies, said the Air Force’s fleet dipping below 5,000 is “absolutely a noteworthy number,” with worrying implications for national security and the service’s ability to project power. Once it drops below that mark, she said, it will be harder for the service to argue in favor of bringing it back up.

“The Air Force has reached a critical danger point in my mind regarding its capacity and ability to fulfill what the nation expects of it, and what the other services depend on,” Penney said.

The issue isn’t limited to the service’s strike assets. Lawmakers routinely raise concerns about whether commanders around the globe will lose vital refueling, reconnaissance, battlefield coordination and more capabilities as the Air Force phases out high-demand fleets. Congress has even barred the service from retiring certain airframes until the military proves it can overcome those capability gaps.

In an April 9 hearing before the Senate Appropriations Committee’s defense panel, ranking member Sen. Susan Collins, R-Maine, expressed her own concerns given the geopolitical environment. She pointed to Ukraine’s experience over the last two years — fighting off Russia’s invasion with a paltry fleet of a few dozen fighters — and questioned whether the U.S. Air Force will have enough aircraft to counter and deter threats across the globe.

“It seems clear to me that not only is quality obviously extremely important, and capability, but quantity matters also, particularly when we’re facing as many threats in such diverse places as we are,” she said.

The trade-offs

Today’s Air Force fleet, while smaller, can carry out missions like precision-guided airstrikes and electronic warfare operations that generals during World War II and the Korean War could only dream of. Tabor said that ability allows the service to “hedge a little bit” on its capacity.

What’s more, other branches of the U.S. military and America’s allied and partner nations in some cases have capabilities similar to the Air Force, Tabor added, potentially making it easier to cover more regions.

Advancements in precision targeting have rendered obsolete the mid-20th century tactics of sending wave after wave of first- and second-generation bombers against a target, raining down scores of munitions with the hope that one will hit the mark. Instead, a single B-2 Spirit — or even in years to come, an in-the-works B-21 Raider, touted by manufacturer Northrop Grumman as the first sixth-generation aircraft — can travel long distances and destroy a target that previously would have required multiple fighters and bombers working in concert.

Improvements in range, coupled with the stealth capabilities of the F-35 Joint Strike Fighter, F-22 Raptor, B-2 and the eventual B-21, have also revolutionized the Air Force’s ability to safely hit targets worldwide. And leaps forward in satellite technology, among other platforms that provide intelligence, surveillance and reconnaissance, have reduced the need for spy planes that once streaked across hostile airspace at Mach speed, snapping photos along the way.

The Air Force plans to retire 250 aircraft in FY25, which would exceed the number of aircraft it plans to bring on, resulting in a reduction of 129 aircraft.

Those old and outdated aircraft slated for retirement include the A-10 Thunderbolt II and older F-15 Eagle fighters, which the service believes would not be suited for a war against an advanced adversary such as China. The service is also eyeing some F-22s for retirement, among other aircraft types, given they would cost too much to prepare for combat. The service expects its downsizing measures will free up money and resources for more modern aircraft.

“They were phenomenal aircraft in their time,” Tabor said of the A-10 and F-15C. “You don’t have to go very far to find someone who will talk about the effects of A-10s on the battlefield. But the reality is, they’re simply no longer viable in today’s fight, and certainly not in tomorrow’s — particularly at the cost associated with keeping them.”

The Air Force also wants to dial back its planned purchase of F-35A and F-15EX Eagle II fighters, as it focuses its spending in FY25 on the research and development of future advanced aircraft, such as the Next Generation Air Dominance program. That effort seeks to craft an even more capable fighter, plus artificial intelligence-powered drones known as collaborative combat aircraft.

“We’re forced to make a choice between two things: We can either maintain legacy force structure, and ultimately what that means is maintaining units and maintaining basing in any location that you want to pick, or modernizing,” according to the deputy chief of staff for plans and programs, Lt. Gen. Richard Moore. “Unfortunately, what’s happening is we’re trying to do both.”

But congressional reluctance about the Air Force’s planned retirements have prevented the service from shifting to the modernization effort it wants, he said in April at an Air and Space Forces Association event.

“We’re being restricted from divesting legacy force structure,” Moore said, adding that the service is “having to slow down modernization.”

That’s one reason the Air Force struck six F-35As and six F-15EXs from its planned purchase in FY25, he noted, as well as reducing its buy of MH-139 Grey Wolf patrol helicopters.

“To maintain legacy force structure and try and modernize, we’re hollowing out the force,” Moore said.

‘Modernization death spiral’

Harrison, the analyst at AEI, said the fleet’s reduction is similar to that occurring among other armed services, even as defense budgets grow larger each year. Much of those budgetary increases go to rising costs for personnel, operations and maintenance, he added.

“When you’ve got recruiting and retention challenges, your force becomes more expensive,” Harrison said. “When you’ve got older aircraft still in the inventory — KC-135 [tankers], B-52s that are older than 90% of the people in the Air Force — those are going to cost more to operate and maintain as they age. When you replace those old systems, those advanced aircraft often cost even more to operate and maintain.”

Budgetary restrictions are also pinching the Air Force; Congress last year passed the Fiscal Responsibility Act, which capped the Defense Department’s FY25 budget and forced the Air Force “to make some hard choices,” service Secretary Frank Kendall said, such as buying fewer F-35s and F-15EXs.

In addition, a long-overdue “bow wave” of modernization is crashing down as the Air Force seeks to simultaneously upgrade its fighters, bombers, tankers and intercontinental ballistic missiles, Harrison said.

“They’re trying to continue all of these new development programs,” Harrison said. “The reality is, it’s just squeezing the budget, and there’s not at much left at the end to procure these things in quantity.”

Over the last two decades, Penney said, the Air Force’s modernization requirements took a backseat to the need to fund the wars in Iraq and Afghanistan. During this time, the service heavily flew aircraft such as the B-1B Lancer, curtailed the F-22 program earlier than expected, and delayed an effort to build a new bomber that eventually became the B-21 Raider.

“That forced the Air Force into … all these service-life extensions, and limping along [with] the fleet that it had until it got [to] today, where everything’s breaking at the same time,” Penney said.

“It is a crisis that we should have anticipated,” she added. “The Air Force needs to not only recapitalize, but it has to grow its force, and the demand signal on it is enormous.”

The result, Harrison said, is that the Air Force is in danger of falling into a “maintenance and modernization death spiral.”

In such a spiral, he explained, the fleet is aging, stretched thin and in dire need of modernization. Because the service has to keep its existing fleet flying — to avoid a capabilities gap — it must spend its limited money on maintaining and extending the life of those older aircraft. But then, he added, the Air Force has less money to buy the new replacement planes it sorely needs.

“How do you pull out of a death spiral?” Harrison said. “That’s the challenge for the Air Force over the rest of this decade.”

And as the number of planes in the Air Force decreases, Penney said, the service may struggle to retain experienced pilots. If they aren’t getting the cockpit time they need because there aren’t enough planes, she added, they might leave and take higher-paying jobs in the private aviation industry.

“It is a slippery slope that the Air Force is already in because … they just can’t retain pilots,” Penney said. “It’s the pilots, it’s the maintainers, it’s the [logistics airmen], it’s the intel ops [at risk of leaving the Air Force]. The entire ecosystem that surrounds a combat capability — you lose all of that knowledge.”

Harrison said the upcoming drop below 5,000 aircraft worries him less than the pattern it represents.

“It’s the trend line that matters, more so than the absolute number itself,” he said. “And the trend line is not sustainable.”