Sticker shock surrounding the F-35 tends to coalesce around a single, punchy number: “the $2 trillion fighter.” The figure appears to be a price tag, but it’s more like a life invoice decades of flight, maintenance, upgrade, training, fueling, and sustaining a fleet that will be relevant long after the midpoint of the century. The engineering tale hidden within the headlines is less about buying and more about sustaining a software-defined stealth fighter for generations.
The total cost estimate of the program is often quoted at around 2.1 trillion dollars, which the Joint Program Office has said takes into account a 94-year life cycle from 1994 through 2088. This is important because “then-year” costing locks in estimates of future inflation; the Joint Program Office has said that about 1 trillion dollars of the total is driven by inflation over this period of time. This is a massive top line, but it is also a century-scale project, not a typical aircraft acquisition.
The airframe piece of the equation is only half of the calculation. Sustainment is the larger number, as thousands of aircraft rack up flight hours, depot visits, software updates, and parts usage every year. Watchdog journalism has documented the sustainment estimates increasing from $1.1 trillion to approximately $1.58 trillion between 2018 and 2023, while use and availability decreased during the same period, summarized as sustainment costs continuing to rise. This is, in engineering parlance, the “tail” that wags the dog, as the aircraft’s low observable materials, carefully controlled tolerances, and digitally enabled maintenance process translate every flight into a logistics event downstream.
This is further complicated by what the F-35 is intended to replace. The aircraft was designed to merge roles that were once distributed across several types: fighter, strike, and reconnaissance, for three U.S. services and a significant number of allies. The magnitude of the program is integral to the cost story, as the Pentagon has planned for the procurement of approximately 2,456 U.S. production aircraft, and over 990 aircraft had been manufactured as of March 2024, according to a a Congressional Research Service program overview. A program of this size provides the potential for economies of scale, but it also represents an industrial need that cannot be scaled back without consequence.
Modernization is the other factor that has remained a constant cost driver, since the strength of the platform is inextricably linked to its software and computing infrastructure. Block 4 and Technology Refresh 3 are expected to add to the weapons integration, sensors, communications, and electronic warfare capabilities, which ensure that the aircraft remains relevant in the face of emerging threats. However, the very process of modernization has turned out to be a challenge in terms of scheduling and integration, since the Defense Department expected that Block 4 would not be finished until 2031, according to a timeline estimate by the Government Accountability Office.
It is not just the high-tech aspects of the program that are important. For instance, the impact of delays in the delivery of aircraft and engines, training rates, spare parts positioning, and depot maintenance schedules is complex. The story of the F-35’s digital sustainment, from ALIS to ODIN, is one way of saying that this is a networked aircraft whose availability is as much a function of data and supply chains as it is of aerodynamics and engines. The net effect is that “$2 trillion” is a stand-in for something more specific: the choice to build a stealth force that is long-lived and continuously modernized on a shared architecture. The spending is front-loaded in sustainment and modernization because that is where the engineering is keeping a complex, low-observable, software-intensive system ready to fly, deploy, and evolve over multiple decades.
