Estimates from the Government Accountability Office found that projected costs to sustain the U.S. military's acquisition and maintenance of 2,500 F-35 aircraft will force the service to make cuts.
The U.S. military projects spending $400 billion to purchase the aircraft and another $1.27 trillion to operate and sustain them, costs that GAO calls "unaffordable" in the new report, published Wednesday.
That could affect the Pentagon's planned purchase of Lockheed Martin-made jets or reduced flying hours, GAO said.
Military services currently face tens of billions of dollars in sustainment costs, with the U.S. Air Force facing the greatest potential increase in costs, according to the GAO analysis, which was first reported by Defense News.
GAO recommended the Air Force reduces sustainment costs annually by $3.7 million by 2036, otherwise, the branch will spend $4.4 billion more than it could afford.
The Department of Defense would face the remaining costs of a $6 billion gap between the cost of sustaining the F-35s and what it could afford.
Air Force Chief of Staff C. Q. Brown said the service might even be willing to cut the F-35A program and buy a less expensive "fourth-gen plus" fighter to replace its oldest F-16s, Air Force Magazine reported.
In its fiscal 2022 budget request, the USAF proposed cutting more than 100 aircraft to save $1.4 billion for research and development.
The Marine Corps needs to cut its F-35B cost per aircraft by 26% and F-35C cost by 14% by 2036 or risk incurring nearly $900 million more than it could afford, GAO added.
