The mission capable rate, which measures the percentage of time aircraft can perform at least one of their tasked missions, dropped from 67% in fiscal 2021 to 44% in fiscal 2025, GAO found.

The full mission capable rate, the share of time aircraft can perform all assigned missions, slid from 38% to 25% over the same period.

JPO officials told GAO that readiness will likely worsen before it improves, and program documentation suggests improvements may not materialize until late 2026 or later.

…GAO projects the services will face a roughly $1.2 billion annual gap between what their F-35s cost to sustain and what they say they can afford.

Those estimates may understate the problem. GAO noted the fiscal 2027 projections were developed before Operation Epic Fury and may not capture the costs associated with additional flight hours.

Between this issue, expenditures of missiles in Iran, lack of industrial capacity to replace lost material, USA military looks to be the most vulnerable it has been in decades.