The US military has approved the F-35 fighter jet for full rate production, authorizing the move after a five-year delay. Though hundreds of F-35s have already entered US and foreign service, the plane only recently completed mandatory combat simulations.

The Pentagon announced the decision in a press release on Tuesday, saying the F-35 had finished digital testing and was now authorized to enter full rate production. Following years of delays, defense acquisition under secretary William LaPlante hailed the news as a “major achievement” for the fighter.

While the milestone was originally scheduled for 2019, the jet encountered a series of problems while training in the Joint Simulation Environment (JSE) – which aims to emulate combat scenarios with enemy warplanes and air defense systems. The military required the F-35 to undergo 64 JSE tests before it could be cleared for full production, which did not occur until the summer of 2023.

However, with arms giant Lockheed Martin already churning out the F-35 at full capacity, the decision is largely symbolic, merely signaling the Pentagon’s confidence in the jet. Lockheed has delivered nearly 1,000 F-35s to the US military and foreign allies, even as the aircraft was plagued by major design flaws which required upgrades to remedy.

Despite the improvements, however, a Pentagon review published in January found that the “operational suitability” of the plane still remained “below service expectations and requirements,” also reporting “critical failures” in several key F-35 components.

A recent Government Accountability Office report also noted massive cost overruns and production delays for the warplane, observing that the cost of F-35 upgrades had exceeded initial estimates by billions. The report dubbed the plane the Pentagon’s “most expensive weapon system program,” and concluded that the total cost to buy, operate and sustain the F-35 would ultimately exceed $1.7 trillion.

The full rate production decision came just days after the Pentagon announced that the Air Force’s F-35A variant had been authorized to deploy nuclear weapons, now allowing it to carry the B61-12 thermonuclear gravity bomb.

This article was originally featured at Antiwar.com and is republished with permission.