A U.S. Marine Corps F-35B Lightning II lands during flight operations aboard Wasp-class amphibious assault ship USS Boxer in the South China Sea, June 10, 2026. (Nicole Stuart/U.S. Marine Corps)
WASHINGTON — The Pentagon plans to spend an additional $13.7 billion through 2031 to boost declining readiness rates of the F-35 jet, but issues such as constrained industry capacity to meet increasing demand for parts could “threaten its success,” according to a government watchdog report.
Since 2021, the F-35 fighter jet sustainment costs have continued to increase, but the aircraft has not met performance goals, and performance has continued to trend down.
According to the report:
The mission capable rate (percentage of time the aircraft can perform one of its tasked missions) declined from 67% to 44%.
The full mission capable rate (percentage of time the aircraft can perform all of its missions) declined from 38% to 25%.
In a new report published Thursday, the Government Accountability Office found that the Joint Program Office will be reliant on the private sector to deliver more than $7 billion in additional parts and other materials to increase the rates at which the aircraft are deemed capable of completing missions.
The $13.7 billion includes about $8 billion for the Air Force, $3.2 billion for the Navy and $2.6 billion for the Marines, according to Pentagon program office figures in the report.
The Defense Department currently sustains and operates more than 800 F-35s and plans to buy an additional 1,700 by the mid-2040s.
In addition, the GAO found the Defense Department paid its contractor hundreds of millions in incentives since 2020 to improve F-35 readiness. These incentives, however, haven’t been effective.
“We found that JPO’s use of contract incentives failed to incentivize contractors to achieve air vehicle readiness requirements,” the 62-page report states.
The Defense Department uses the F-35 for a wide range of missions across the Marine Corps, Navy and Air Force. The aircraft has been used during the recent war with Iran.
GAO made three recommendations, including one involving the sustainment strategy, referred to as the Global Support Solution Reset. It asks the Pentagon to develop risk mitigation plans to ensure that future incentive approaches better achieve the desired performance for sustainment contracts.
“(The Defense Department) did not provide formal comments on this report but noted in draft comments that it concurred with the recommendations,” according to the report.
