The Air Force is asking Congress for a major infusion of cash into a little-known fund that manages spare parts In its 2027 budget request, as the service focuses on improving aircraft readiness.
The proposed ’27 budget calls for $4.2 billion in appropriations for the Air Force’s Consolidated Sustainment Activity Group, or CSAG, supply division, according to documents posted by the Defense Department’s comptroller.
The CSAG is part of the Air Force Working Capital Fund, one of several such funds within the Pentagon. These funds are meant to function almost like businesses, procuring commercial goods and services and “selling” them to other Pentagon organizations, which use annual appropriations to pay, according to a Congressional Research Service report. The Air Force fund provides maintenance services, weapon system parts, medical supplies, base supplies, and transportation services.
When they’re established, these funds get an initial appropriation to get started, but after that, they’re meant to be largely self sufficient and don’t need much in the way of annual appropriations. The Air Force Working Capital Fund, for example, had more revenue than expenses in fiscal 2026 and got just $143 million in appropriations.
However, the Pentagon can provide additional capital for funds through annual appropriations. That appears to be the case in the 2027 budget—the overall request for the Air Force Working Capital Fund is $4.4 billion, a 3,012-percent boost over 2026.
Almost all of that is going to CSAG, which has not requested direct appropriations since 2021, according to budget documents. The rest of the working capital fund budget would provide $195 million for supply management.
The Air Force was unable to provide comment at the time of this story’s posting.
The Air Force operates the CSAG to manage its supply chain for spare parts and other repairable and consumable items, often at the depot level. Its supply division provides logistics support services such as requirements forecasting, cataloging spare parts and other items, procurement, repair, data management, and distribution millions of parts annually.
CSAG also has a maintenance division to oversee repairs and sustainment of weapons systems such as aircraft and engines.
Mark Gunzinger, a retired B-52 pilot and director of future concepts and capability assessments for the Mitchell Institute for Aerospace Studies, said the dramatic increase in funding for CSAG’s supply division is likely meant to help the Air Force improve its ailing aircraft readiness rates, among other issues.
“The Air Force has had a huge backlog of [maintenance] requirements, and is finally nibbling away at that,” Gunzinger said. “This is all about readiness.”
Aircraft readiness rates in the Air Force have steadily declined in recent years, drawing concern from both outside observers and top service leaders. In 2024—the last year for which the Air Force released statistics—the service had a fleet-wide mission capable rate of 62 percent, the lowest in recent memory. That meant barely more than six out of every 10 aircraft were able to carry out their missions on an average day in 2024. (The Air Force declined to release mission capable rate statistics for 2025.)
Air Force Chief of Staff Gen. Kenneth Wilsbach made improving readiness a top priority upon taking charge of the service in November 2025.
“We fly and fix to fight and win our nation’s wars,” Wilsbach said during his assumption of responsibilities ceremony.
But a dearth of critical spare parts has hindered the service’s effort to get more planes in the air. For example, spare parts shortages for the six-decade-old B-52 Stratofortress has led the Air Force to hunt for alternative sources to remake those out-of-production parts, and maintainers regularly have to cannibalize parts from other B-52s.
Lt. Gen. Scott Pleus, who at the time was acting vice chief of staff, said at a February 2026 Mitchell Institute event that Wilsbach and Air Force Sec. Troy Meink have made improving readiness a top priority—and buying more spare parts is a critical step towards that goal.
“We’ve got to buy parts,” Pleus said. “We’ve got to have the parts available so that … maintenance folks that are out there, wrenching on the flight line each and every day, in the cold, in the rain, in the heat, have the parts they need so they can fix those airplanes, and then we can get them airborne again.”
And with the overall Defense Department budget request hitting an all-time $1.5 trillion, Gunzinger said the Air Force is concentrating on getting more aircraft flying.
“The Air Force made a big push in this budget to address its weapon system sustainment accounts and war reserve materiel accounts,” Gunzinger said. “Which is far more than just munitions. It includes flying hours, spare parts, and other components to improve the readiness of its aircraft and its crew force.”