The Marine Corps’ long delayed F-35B jet is ready to fly. Somewhere. Sometime. The Marine Fighter Attack Squadron 121 is the first unit with the F-35 variant in its fleet, and the military branch ordered 10 of the jets.Of course, after $400 billion, it still can’t win in a dog fight against other, older jets. (Although F-35 proponents would point out that the F-35’s long-range strike capabilities ostensibly mean it would never be in one in the first place.) The F-35 has been in development so long that the money has been spread out for more than a decade. In 2014, it “only” cost $8.4 billion. For context, the development of the F-35 cost as much as building roughly 40 Nimitz-class aircraft carriers .“Congratulations to the Marine Corps for leading the way,” Lt. Gen. Christopher Bogdan said in a press statement. “The F-35 government and industry team will continue to deliver on our commitments to field the world’s finest combat aircraft for the United States and our allies.“Our congratulations go out to Lockheed-Martin and the Department of Defense on this momentous occasion. The most expensive weapon ever procured is ready to fly. All 10 of them.John WenzWriterJohn Wenz is a Popular Mechanics writer and space obsessive based in Philadelphia. He tweets @johnwenz.