How is it that the technologically most sophisticated air force ever has fewer than six out of ten planes ready to fly? The statistics are stark: during fiscal 2024, the U.S. Air Force fleet-wide mission-capable rate declined to 62 per cent its lowest level ever, taking some 1,900 planes out of service on any given day. For a force with peer rivals who are increasing their capability, the convergence of ageing fleets, reduced readiness, and long modernisation is minimising the margin of superiority long assumed.
1. A Historic High in an Ageing Fleet
The average age of the fleet is now more than 31 years, up from 17 years in 1994. Eight fleets, including the B-52 Stratofortress, KC-135 Stratotanker, and C-5 Galaxy, are more than half a century old. The B-52H, in service since the 1960s, has a mean age of 63.5 years and will fly well into the 2050s. The “tired iron” fleets more and more “learn new and interesting ways to break,” since maintainers are having trouble finding parts from extinct manufacturers, fabricating replacements, or cannibalising other planes.
2. Freefall Readiness Rates
Major fighter mission-capable rates have unravelled. The F-35A Lightning II, the Air Force’s pride of fighter stock, fell from 69 per cent in 2021 to 51.5 per cent in 2024, a long way from the Air Force’s previous 80 per cent goal. The A-10 Warthog fell from 72 per cent to 67 per cent and the F-16C from close to 72 per cent to 64 per cent over time. The CV-22 Osprey fell as low as 30 per cent in 2024. Heather Penney of the Mitchell Institute cautioned, “Readiness is often a lagging indicator; those aren’t even today’s MC rates,” and forecasted further decline.
3. Structural Reasons for the Decline
The crisis of readiness is caused by mutually related factors: spare part shortages, manpower shortfalls in maintenance, and depot backlogs. The Air Force spends around $4 billion on parts each year but suffers from forecasting errors and flying hour variances that lead to supply-demand imbalances. Prioritising operational units deployed abroad still cannot fully compensate for logistical delays or environmental degradation in deployed areas.
4. The B-52J Modernisation Struggles
To keep the B-52 flying longer, the $48 billion B-52J program will incorporate new Rolls-Royce F130 engines, digital fly-by-wire flight control systems, and the Raytheon AN/APQ-188 AESA radar. But the cost of the Radar Modernisation Program jumped from $2.3 billion to $3.3 billion, causing a Nunn-McCurdy “significant” violation. Engine replacement is three years behind schedule and $2.5 billion more expensive. While the AESA technology provides ground mapping, threat watch, and potential electronic warfare capability, the delays threaten to make the bomber dependent upon antiquated systems well into the next decade.
5. The B-21 Raider’s Promise
The Northrop Grumman B-21 Raider, first disclosed in 2022 and first flown in November 2023, is a deep-penetrating stealth bomber with increased range, lowered radar cross-section, next-generation sensors, and open architecture to permit future upgrades. Procurement is for at least 100 aircraft with a unit price estimate in 2022 dollars of $660 million. Early operational deployment is in 2026, but even prompt rollout cannot replace the ageing B-1B and B-2 fleets swiftly.
6. NGAD: Sixth-Generation Fighter
The Next Generation Air Dominance program rethinks the fighter as a “system of systems” that includes a sixth-generation manned airplane with as many as 1,000 unmanned Collaborative Combat Aircraft. Powered by adaptive cycle engines such as Pratt & Whitney’s XA103, NGAD will provide greater survivability, range, and sensor fusion in contested airspace. Open architecture will enable quick upgrading but one that will cost $300 million an aircraft, and the rate of procurement will be essential to reversing force structure decay.
7. Comparative Disadvantage Against China
China’s People’s Liberation Army Air Force has put 1,300 combat-capable fighters on duty in 14 years, including 320 fifth-generation J-20s, and is manufacturing more than 120 J-20s per year, more than twice as many as the U.S. Air Force buys. Wargame simulations demonstrate that, based on estimated rates of loss of 5 per cent per day, American operational strength could be reduced by two-thirds after three weeks in a high-end war, with little capacity to fill in losses because of incremental industrial ramp-up.
8. Training and Human Readiness Deficiencies
Pilot proficiency has also suffered along with aircraft readiness. Fighter pilots now manage fewer than 1.5 sorties per week, well below Cold War standards of more than three. Bomber aircrewmen have similarly greater deficiencies, with some units unable to generate peer-level mission demands. The Jan. 2024 incident of a B-1 on a routine approach highlighted the danger of low sortie rates and unchanging skills.
9. The Cost of Inaction
Rebuilding capacity, capability, and readiness could require $30–40 billion annually above current budgets. Without decisive action, the Air Force risks ceding air dominance in the Indo-Pacific, with potential disruption to $5 trillion in annual trade and erosion of U.S. strategic credibility. As Air Force Chief of Staff Gen. David Allvin cautioned, “I don’t want to be here next year saying we’re no longer dominant. So we’ve got to work on this.”
