Delays for Pentagon's most expensive weapon system getting worse, at $200 billion over budget

The contractors behind the Pentagon's most expensive weapon system continue to deliver engines and aircraft late, a trend that has worsened in recent years, according to a new report.

The U.S. Government Accountability Office, which serves as the research arm of Congress, found that late deliveries were partially caused by manufacturing issues and a shortage of parts for the U.S. Department of Defense's F-35 Lightning II, a stealth strike fighter.

The F-35 Lightning II is the most advanced and costly weapon system in the U.S. arsenal. The Pentagon estimates the F-35 program will cost over $2 trillion to buy, operate, and sustain over its lifetime. The program was already behind schedule.

"The program, however, is also more than a decade delayed and has cost $209 billion more than originally planned," according to the GAO report.

Lockheed Martin is the prime contractor for the F-35 aircraft and Pratt & Whitney is the prime contractor for the engine. The F-35 program completed initial operational testing and achieved full-rate production in March 2024. Nearly everything the two contractors delivered in 2023 was late.

"The program continues to experience production delays," according to the report. "Specifically, the contractors delivered all engines and almost all aircraft late in 2023."

Pratt & Whitney did not deliver any engines on time in 2023. Most were more than two months late, on average. In 2022, the average delay was one month late. Defense Contract Management Agency officials said hardware issues were responsible for late engine deliveries over the past year. Late engine deliveries have yet to affect aircraft production due to an engine inventory buffer, according to the report.

Lockheed Martin delivered 91% of aircraft late in 2023. That's the highest proportion of late deliveries over the past six years and is almost double the percentage of late deliveries in 2022, according to the report. The report cited a shortage of parts and manufacturing issues, among other problems.

The cost of the F-35 program has increased. Specifically, sustainment cost estimates have increased 44%, from about $1.1 trillion in 2018 to about $1.58 trillion in 2023. One reason for the increase in cost estimates is the extension of the aircraft's service life. The Pentagon plans to use the F-35 through 2088.