You need to fix alarming mission-capability rates and rising sustainment costs for the Air Force’s F-35A fighter jet, senators told the service’s chief-of-staff nominee on Thursday. “The F-35 remains the most advanced fighter in the world, but too many of them are sitting idle on ramps. The readiness rates of our aircraft continue to fall short of Pentagon goals. This is known on this side of the ocean and around the world,” Sen. Roger Wicker, R-Miss., the Senate Armed Services Committee chairman, said during Thursday’s hearing. “The Air Force cannot protect power if its most advanced fighter cannot get off the ground.” The warning was directed at Gen. Kenneth Wilsbach, the former head of Air Combat Command and Pacific Air Forces, who was nominated last month to serve as the service’s top uniformed leader.

The current Air Force chief of staff, Gen. David Allvin, unexpectedly announced in August that he would retire, effective in November, after his ties to a massive reorganization effort focused on China seemingly broke with the Pentagon’s renewed homeland focus. Wilsbach was not questioned by lawmakers about Allvin’s sudden departure and was not heavily grilled on the Trump administration’s domestic deployment of the National Guard or ongoing military actions against alleged drug-runners. Senators mainly focused on technical problems facing the Air Force—and in particular, the F-35’s parts and maintenance problems. F-35 maker Lockheed Martin has regularly delivered the jets late and without necessary upgrades, according to a Government Accountability Office report released last month. Between 2019 and 2023, mission-capable rates for the fifth-generation fighter have floated between 71 and 51 percent while sustainment costs ballooned, another GAO report found last year. Sen. Jack Reed, D-R.I., the SASC’s ranking member, told Wilsbach that idle F-35s need to get flying because pilots sitting “around in a simulator all day” will harm aviator retention. Wilsbach agreed and told the lawmakers that his service’s weapons-sustainment accounts need more money to fix the problem.

“We definitely have to invest in those accounts so that the parts are on the shelves when the aircraft flies,” the general said. “The problem with the F-35 is now they have to wait for the part to be shipped…All that time where it’s sitting waiting for that part is downtime where we can’t use the aircraft to train.” The 2026 defense budget working through the cogs of Congress would allow for the purchase of 47 F-35s, including two dozen A-models for the Air Force. The massive defense-focused reconciliation spending bill passed this summer included no additional funding for the F-35. Discretion for implementing those funds ultimately falls to the Defense Department. When asked by Wicker if Wilsbach would “carry out congressional intent” with reconciliation funds, the general declined to explicitly answer and said he “will carry out the funding in accordance with the law” and “will strive to do my best.”

One of the major efforts led by Allvin and former Air Force Secretary Frank Kendall was a sweeping organizational shift for great power competition, an influx of increased strategy and spending focused on countering China. Wilsbach did not commit to continuing these reoptimization efforts. He did acknowledge during questioning by Sens. Mazie Hirono, D-Hawaii, and Mark Kelly, D-Ariz., that China was a threat to national security and worth further investment from the committee. Mirroring comments made by Air Force Secretary Troy Meink last month, Wilsbach stated in submitted written answers to lawmakers’ policy questions that both the homeland and the Pacific would be prioritized. “Homeland Defense is our top priority. At the same time, our Service needs to be able to project power into critical regions to prevent wars when possible, or to win them if and when we must,” Wilsbach wrote in the document. “The Air Force must deliberately preserve our high-end readiness for the nation’s most consequential challenges, such as that posed by China in the Western Pacific.”

When asked outside of his hearing Thursday morning if he planned to support those past reoptimization efforts, Wilsbach said, “That’s outside of my lane,” and added that it is Meink’s decision to make. “I’ve had some private conversations,” the general said, and said he wouldn’t be sharing details of those talks with reporters.