The F-35 Joint Strike Fighter is the costliest weapons program in U.S. history.

The Pentagon will pay about $107 million apiece, or about 4 percent less than the previous contract, for each of the 22 conventional takeoff and landing jets in the deal, sources familiar with the agreement said this week.

It paid $111.6 million for the Air Force version of the plane in the previous contract.

The deal, the fifth Low Rate Initial Production contract, also includes three Marine Corps versions of the plane, which can land vertically, and seven Navy models, which can be used on aircraft carriers.

"With the ... contract finalized, we look forward to completing the build of these fifth-generation aircraft and delivering them to our war fighters," said Orlando Carvalho, the Lockheed program manager for the F-35.

Loren Thompson, a defense consultant with close ties to Lockheed, said in a blog on Friday that the cost of the Air Force variant of the plane should fall to $64 million apiece by the 10th lot if the ramp-up in production unfolds as now planned.

(Reporting by David Alexander; Editing by Will Dunham)

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