WASHINGTON — The Air Force would get six more F-15EX Eagle II fighters in fiscal 2025 under the House Armed Services Committee’s proposed version of the fiscal 2024 National Defense Authorization Act.

If enacted, the proposal could boost the Air Force’s effort to buy more new fighters to modernize its fleet.

The service’s budget documents show it plans to request 24 Boeing-made F-15EX jets in 2025, the same amount as in 2023 and 2024. But the chairman’s markup of the draft NDAA, released Monday evening, includes an additional $92 million in advance procurement funding to buy six more of those fighters in 2025.

That would bring the service’s total Eagle II buy to 30, and bring advance procurement funding for the F-15EX to $320 million in 2024.

The committee, chaired by Rep. Mike Rogers, R-Ala., moved to increase the Air Force’s fighter purchases to speed up the pace at which it is replacing older, retiring fighters, a senior congressional aide told Defense News. The service plans to retire 801 tactical fighter aircraft over the next five years while bringing on 345 new F-35s and F-15EXs.

When combined with the Air Force’s plan to buy 48 new F-35A fighters — the service’s expected standard annual purchase going forward for the next few years — the increased number of F-15EX purchases would mean the service would get 78 new fighters in 2025.

That would be more than the 72 fighters top Air Force leaders regularly say need bought on each year to both modernize the fleet and lower fighters’ average age.

If the service can’t buy that many annually, top generals warn, it won’t have enough new fighters to replace aging and retiring fighters such as the F-15C.

For years, the Air Force frequently did not ask for that many fighters in its budget requests, nor did lawmakers approve those amounts. In 2023, for example, Congress approved a total of 67 new fighters for the Air Force, 24 F-15EXs and 43 F-35s.

That changed in 2024, when the Air Force asked for the full 72 fighters it says it needs. Lt. Gen. Richard Moore, deputy chief of staff for plans and programs, said in April that he believed the service would ask for 72 fighters again in the future.

But mistakes and quality issues on the F-15EX’s production line have caused the program to slip at least six months. The Government Accountability Office said in a report released in June that Boeing mis-drilled windscreen installation holes on four F-15EXs, and the holes will need to be redrilled.

GAO also highlighted other unspecified supplier quality problems on a critical forward fuselage component needed to ensure the F-15EX’s safety of flight.

The Air Force currently has two test F-15EXs. Boeing was originally scheduled to start delivering the first of six more F-15EXs in December 2022 before the production problems caused delays. It is unclear when the deliveries of the latest batch will take place, but it could begin later this summer.

The Air Force plans to buy 104 F-15EXs in all. The new version of the fourth-generation F-15 fighter is upgraded with advanced avionics and better electronic warfare capabilities.