The number that matters is 47. That is how many fighters the United States Air Force is short of the minimum Congress wrote into law — not an aspiration, not a target, a statutory floor. And the service has been below it since at least May.

The figure surfaced again this week in a Congressional Research Service report, Air Force Fighter Force Structure: Background and Issues for Congress, published on 4 September 2026 and picked up across the American defence press on Monday and Tuesday. The CRS is Congress’s own in-house analyst. When it tells lawmakers the Air Force cannot get where it says it is going, lawmakers tend to notice.

The gap between what the Air Force has, what the law requires, and what the Air Force says it needs by 2035 is enormous. And the fleet it is flying in the meantime is, on average, older than the pilots flying some of it.

Two ways to count an air force

Part of what makes this argument slippery is that the Air Force and Congress are not counting the same things.

The legal requirement is written against primary mission aircraft inventory, or PMAI — the jets assigned to do the mission, and nothing else. The Air Force argues that this undercounts reality, because PMAI leaves out roughly 15 per cent of the aircraft actually assigned to combat-coded units: the backup airframes and the attrition reserve that keep squadrons flying.

So in its October 2025 report to Congress, the service proposed a different yardstick: Combat-Coded Total Aircraft Inventory, CC TAI, which counts those aircraft in. Measured that way, the fleet in fiscal 2026 is 1,271 rather than 1,098, and by fiscal 2030 it would be 1,304 against a PMAI of 1,146.

Notice what that second number does. On the Air Force’s own projection, PMAI creeps back over the statutory 1,145 line only in fiscal 2030 — and only just, by a single aircraft. The law, meanwhile, is still written against PMAI. Changing the yardstick does not put jets on the ramp.

The 1,558 problem

The headline number in all of this is 1,558: the crewed, combat-coded fighter force the Air Force concluded in 2025 it would need by 2035 to fight with what it calls low risk. That analysis came in a report Congress itself had ordered under the 2025 National Defense Authorization Act.

That is the phrase the report uses for what the force has to do over the next decade. Getting there means buying at rates the service has not sustained in a generation — on the order of 100 F-35As and 24 F-15EXs a year by 2030 — and the CRS adds the qualification that makes the whole plan wobble: it needs both the money and the industrial capacity, and the Air Force is not projected to have the obligation authority to pay for that production rate.

In other words, the plan is a plan. An Air Force official quoted when the 2025 report emerged described it as aspirational, achievable only with a significant budget increase.

An air force older than the US Navy’s, three times over the RAAF’s

The average American fighter is about 27.4 years old. That is the oldest fighter fleet of any US service, and older than that of many partner nations: roughly twice the average age of the US Navy’s fighters, and around three times that of the Royal Australian Air Force.

Age is not just a talking point. The CRS report describes a near-perfect correlation between the rising average age of the fighter fleet and falling aircraft availability rates. Old jets need more maintenance, wait longer for parts, and spend more of their lives in a hangar rather than on the flight line. The inventory number on paper and the number of jets a wing commander can actually generate on a Tuesday are two different things, and the gap between them widens every year.

Congress keeps saving the jets it also wants replaced

The Air Force’s escape route from an ageing fleet is to retire the oldest aircraft faster and spend the savings on new ones: the legacy F-15C and D models, the A-10C, and the oldest F-15Es and F-16C and Ds.

Congress has repeatedly refused to let that happen at the pace the service wants, for a reason that is not unreasonable: lawmakers do not want to lose capacity before the replacement exists. The statutory framework currently restricts retirement of the F-22 and the F-15E, and Congress has imposed its own restrictions on A-10 retirements as well.

So the service is caught between two of its own oversight bodies: one telling it the fleet is too small, the other refusing to let it shrink the part it wants to shed in order to grow the part it wants to buy.

A background film on the F-35 and where it sits in the future US Air Force fighter force.

The F-47 does not arrive in time

The long-term answer is supposed to be the F-47, the sixth-generation fighter coming out of the Next Generation Air Dominance programme, designed for exactly the contested airspace where an F-35 and an F-15EX would have a harder time. But an aircraft in development, test and early production does not fill a squadron this decade. The Air Force has to fight with what it has while the F-47 grows up.

Which leaves the other new thing: Collaborative Combat Aircraft, the uncrewed wingmen. Here the counting question returns. The 1,558 objective applies to crewed aircraft only; CCAs are explicitly excluded. The Air Force’s own 2025 report calls them a force multiplier rather than a replacement for manned fighters, and the CRS repeats that framing — while noting the obvious temptation, that CCAs let you field a larger overall force for a given budget.

That is the fight the next few defence budgets will be about. Not whether the Air Force is short of fighters — by its own notification to Congress, it is, by 47 — but whether the answer is more crewed jets it cannot currently afford, or a different definition of what counts as a fighter.

Sources: Congressional Research Service report R49338 (4 September 2026); Department of the Air Force Long-Term USAF Fighter Force Structure report (October 2025); The Aviationist; Air Force Times; Stars and Stripes; Defense News.