How much do F-35 Lightning II fighter jets cost in 2026? The answer is very complicated and intertwined with what the air forces want to do with them, the capabilities being sought, what variant is being purchased, whether the customers are part of the development program, and much more. When comparing the F-35’s fly-away costs to other frontline fighter jets, like the F-15EX, Rafale, and Eurofighter, it can be less, but sustainment expenses are higher.