The US military is throttling back on the F-35 as other militaries stock up on the stealth fighter

• The Pentagon's 2023 budget request includes a lower-than-expected purchase of F-35 fighter jets.
• US military officials say the reduction in orders reflects a desire to prioritize modernization.

The $773 billion budget request presented by the Defense Department this week proposed buying dozens fewer F-35s than expected, a reduction that military officials said is being made to focus on modernizing the fighter fleet.

That announcement coincided with Canada's announcement that it would buy 88 F-35s to replace its older fighter jets, making Ottawa the third US ally or partner to sign on to buy the Joint Strike Fighter in recent weeks.

The budget presented on Monday proposes buying 61 F-35s — 33 F-35As for the Air Force and 28 F-35Cs and F-35Bs for the Navy and Marine Corps — in fiscal year 2023, which begins on October 1.

Those totals are down from the 85 jets approved by Congress in the 2022 budget and from the 94 that the Pentagon was expected to request for 2023.

In briefings Monday, service officials said the reductions were about prioritization.

The Navy's F-35 request "did come down" from previous budget outlooks, "and that simply reflects the balance of this budget request as you looked at our portfolios increasing for ship construction and [research and development] while focusing on readiness," said Rear Adm. John Gumbleton, deputy assistant secretary of the Navy for budget.

"Simply, we chose to bring those numbers down," Gumbleton said of the Navy's F-35 request.

At a separate briefing, Gina Ortiz Jones, undersecretary of the Air Force, said 33 more F-35s would "grow" the fleet and cited other investments, such as funding for an advanced engine, that would benefit the F-35.

"But the emphasis is on modernization and mak[ing] sure we have Block 4 as soon as we need it," Ortiz Jones said.

Block 4 is the most recent F-35 standard, and it includes upgrades to the jet's software and other systems. The Air Force has been updating its jets to Block 4 since 2018 and has encountered delays and cost overruns.

"When we look at the F-35 what do we need? Mostly it's the Block 4 capability," Navy Vice Adm. Ron Boxall, director for force structure, resources, and assessment on the military's Joint Staff, said at a different briefing.

"There have been delays in F-35, and again, the delays have also delayed that capability that we want," Boxall said.

Boxall said the Pentagon "took this opportunity" to shape its broader "attack air portfolio," including by buying more F-15EXs, a non-stealth jet better suited for some low-end missions than the F-35.

'Immature, deficient, and insufficiently tested'

In its most recent annual report, the Pentagon's director of operational test and evaluation said that in 2021 the F-35 program "continue[d] to field immature, deficient, and insufficiently tested Block 4 mission systems software."

A more detailed version of the report, which wasn't released but was obtained by the Project on Government Oversight, said the update process of which the Block 4 upgrades are a part "has often introduced stability problems and/or adversely affected other functionality."

The unreleased version of the report described a number of other problems, such as low mission-capable rates and ongoing shortages of spare parts, including engines. A years-long delay on high-end simulated testing has also prevented an official decision on full-rate production of the jet.

Air Force Secretary Frank Kendall worked in the Pentagon acquisitions office between 2010 and 2016, when design issues led Kendall to limit F-35 production for two years to put pressure on Lockheed Martin and to avoid buying jets that would need modernization later.

Kendall told Air Force Magazine in August that the current situation "bears some resemblance" that earlier period.

A person familiar with the Air Force's decision on the 2023 request told Bloomberg that the reduction in F-35 orders was meant to slow purchases of the jet until the Block 4 upgrades could be rolled out.

The 2023 budget has to be approved by Congress, which may modify the F-35 request, but Air Force officials say they still plan to buy 1,763 F-35s.

"We're 15 years into production, and we'll be building F-35s probably another 15 years," Kendall told reporters last week.

"We remain committed to the F-35," Ortiz Jones said Monday, adding that there was "no change to the final buy."

Canada's announcement on Monday came two weeks Germany said it would buy 35 F-35s and six weeks after Finland finalized its purchase of 64 Block 4 F-35s. Nearly a dozen other countries have ordered F-35s, and more than 770 F-35s have been built.

The jet has already seen combat, earning its first air-to-air kills with the Israeli air force. US F-35As and F-35Bs have also conducted airstrikes. Six US F-35s are currently forward-deployed to the Baltic and Black Sea regions amid tensions in Europe.

Despite the F-35's ongoing maintenance and cost issues, pilots have made "glowing comments" about it, Sen. Jack Reed, chairman of the Senate Armed Services Committee, said this month.

"These aircraft are highly capable, but the question that we have to ask — and I think the Air Force is asking — [is] are they sustainable [and] durable," Reed said at a Defense Writers Group event. "Until they answer those questions, I think they're not going to rush in and acquire significant numbers."

"In the meantime, we have what the pilots say is a superb aircraft, which we have to work through," Reed said. "I think once we have reached the point of validation, and particularly observing what they do in Europe, we can be more confident going forward."