The Pentagon says its total aviation inventory will shrink by roughly 10 percent over the next decade because it can’t afford to build and modernize enough planes to keep up with the pace of aircraft retirements, according to a new agency report.

The "Annual Aviation Inventory and Funding Plan Fiscal Years 2017-2046,” submitted to Congress last month and obtained by Defense News, shows the Defense Department’s aviation fleet would drop from 14,516 aircraft in the current fleet to 13,109 aircraft by 2026 – a drop of 1,407.

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The assessment found that the Air Force and Navy’s fighter jet fleets would be hard hit in the coming years, going from 3,327 today to 2,981, a loss of 346 warplanes.

Such a cut would be a major problem for the Air Force. Last year lawmakers directed the service to keep at least 1,900 fighters in its inventory past 2021. Today the service has 1,971 attack aircraft, so the anticipated reduction would bring the Air Force well below that line.

“The Air Force has insufficient resources to maintain the FY 2016 [national defense authorization act] … beyond” 2021, according to the report. “The inventory drop will continue until it reaches its lowest level in 2031.”

Concern has been building for some time that the Air Force’s dogged pursuit of big-ticket items – including the F-35 Joint Strike Fighter, which has cost nearly $400 billion to develop, and a next-generation bomber that could cost well over $100 billion – would squeeze its budget and leave no money for other items.

The language in the report indicates that the problem could become more widespread unless Congress takes action to boost the service’s bottom line.

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But it’s not just fighters that take a hit in the new Pentagon projections.

The airlift and cargo fleet would scale back by more than 900 aircraft by 2026, according to the analysis, going from 5,351 to 4,449.

Meanwhile, the Pentagon’s intelligence gathering and reconnaissance inventory would shrink from 1,145 existing aircraft to 920, a reduction of 225, and 148 training aircraft would also be sent off to the boneyard.

The study isn’t all gloom and doom, though. The military’s number of attack helicopters would rise by 147, jumping from 748 today to 905, and the Navy’s anti-surface and anti-submarine inventory would climb from 598 to 658.