Every time an F-35 Lightning II takes off, a clock starts running. Not just the mission clock — the cost clock. At approximately $42,000 per flight hour, the F-35 is the most expensive fighter to operate in the history of aviation. A single one-hour training sortie costs more than many Americans earn in a year. That number — $42,000 — has haunted the F-35 program since its earliest days. It has been cited by critics as proof the aircraft is unaffordable, by defenders as a figure that is steadily declining, and by Pentagon officials as a problem that must be solved before the Air Force can fly the jet as often as it needs to. But what does that number actually include? Where does the money go? And is it as bad as it sounds?

Breaking Down the Bill

The cost per flight hour (CPFH) is not just fuel. It is everything required to keep the aircraft flying, divided by the number of hours flown. The major components include fuel and consumables, which account for roughly 15–20 percent of the total. The F-35's Pratt & Whitney F135 engine burns approximately 1,350 gallons of JP-8 fuel per hour, depending on the mission profile. At current military fuel prices, that is roughly $5,000–7,000 per flight hour in fuel alone. Depot-level maintenance and parts replacement make up the largest share — roughly 40–50 percent. The F-35 requires regular inspections, component replacements, and software updates. Its stealth coatings need periodic repair. High-temperature engine components wear out and must be replaced. Each of these actions draws from a supply chain that spans thousands of parts sourced from hundreds of suppliers worldwide. Contractor logistics support is another major cost driver. Unlike older fighters where military maintainers handle most repairs, the F-35 relies heavily on Lockheed Martin's sustainment organization for depot maintenance, parts provisioning, and technical support. This contractor dependency adds cost but also ensures access to specialized expertise for a technologically complex aircraft. Personnel costs — pilot salaries, maintainer wages, support staff — round out the total. An F-35 squadron requires a small army of people to keep its jets in the air, and their compensation is baked into the per-hour figure.

Context Matters

The raw $42,000 figure can be misleading without context. The F-15E Strike Eagle — a fourth-generation fighter that the F-35 is partially replacing — costs roughly the same per flight hour. The F-22 Raptor, the Air Force's other stealth fighter, costs about $68,000 per hour. Compared to these aircraft, the F-35A is not uniquely expensive. Where the F-35 differs is in fleet size. The Air Force plans to operate over 1,700 F-35As — far more than any other fighter in its inventory. When you multiply $42,000 by the tens of thousands of flight hours the fleet will generate annually, the total sustainment bill becomes enormous. Even small reductions in the per-hour cost translate into billions of dollars in savings over the life of the program. This is why the Pentagon has set an aggressive target of reducing the F-35A's CPFH to below $30,000. Achieving that goal would require improvements in supply chain efficiency, reduced dependency on contractor support, longer-lasting components, and better predictive maintenance — all of which Lockheed Martin and the Joint Program Office are actively pursuing.

The Readiness Trap

There is a vicious cycle embedded in the cost problem. Because the F-35 is expensive to fly, squadrons fly fewer hours than they need to maintain full readiness. Because they fly fewer hours, pilots get less training. Because pilots get less training, combat readiness suffers. And because readiness suffers, the Air Force must find ways to get more training into fewer hours — which often means more intensive flights that accelerate wear on the aircraft, driving costs back up. The mission-capable rate — the percentage of aircraft available to fly on any given day — has been another persistent challenge. The F-35 fleet has hovered around 55–65 percent mission capability, below the 80 percent target the Pentagon sets for its fighter fleets. Every jet sitting in a maintenance hangar instead of on the flightline represents sunk cost without operational return. Despite these challenges, the trajectory is improving. The CPFH has declined from over $50,000 in early operational years, and Lockheed Martin claims it is on track to push the number below $35,000 by the end of the decade. Whether they get there — and whether the Air Force can afford to fly the fleet hard enough to keep pilots sharp — will determine whether the F-35 fulfills its promise as an affordable workhorse fighter or remains a technological marvel that costs too much to use. Sources: Government Accountability Office, Department of Defense Selected Acquisition Reports, Air Force Magazine