The operational use of the carrier-based joint strike fighter could mark the beginning of the end of the Navy's manned bombing sorties, if the Navy secretary gets his way.

The F-35C "should be, and almost certainly will be, the last manned strike fighter aircraft the Department of the Navy will ever buy or fly," Navy Secretary Ray Mabus said in a speech Wednesday at the annual Sea-Air-Space Exposition outside Washington, D.C. Fighter jocks would still be needed for dogfighting, but Mabus envisions a future when strike missions will be fulfilled by unmanned strike aircraft.

Mabus announced the creation of the N99 Navy staff office for unmanned weapons systems and a new position for deputy assistant secretary of the Navy for unmanned systems.

"Unmanned systems, particularly autonomous ones, have to be the new normal in ever-increasing areas," he said.

The announcement came the same day as a milestone test for the Unmanned Combat Air System Demonstration program, the first of three aerial refueling tests that mark the program's concluding step.

Following the tests, the two UCAS jets will be sent either to an aviation museum or to the Navy's aircraft boneyard in Arizona, Capt. Beau Duarte, Carrier Unmanned Aviation program manager, said in a presentation Tuesday at the expositionSea Air Space Exposition outside Washington, D.C.

"The UCAS-D program was born with the primary role of, 'Okay, let's show ourselves that we can successfully take off and land from the ship, integrate operations around and on the carrier, and work in the pattern [with manned jets],' " Duarte said.

Now that those tests are complete, it's time to retire the program, he added.

Some in Congress, including Senate Armed Services Committee chairman Sen. John McCain, R-Ariz., have called on the Navy to continue testing the aircraft, which have only used about 15 percent of their airframe hours.

That wouldn't be wise, Duarte said, because UCAS is a precursor to the eventual Unmanned Carrier Launched Aerial Surveillance and Strike program, but physically has little in common with it.

"From a Navy perspective, this is the last year of funding," Duarte said. "UCAS, it's a demonstrator, so it's a different architecture, different landing system, from what UCLASS will have."

UCLASS, which Duarte's office envisions as a key part of the carrier air wing of the future, will be able to provide airborne surveillance and strike, though fighter-to-fighter engagements situations will still be carried out by manned jets.

That is still a few years off, though, Duarte said. A strategic portfolio of review, for UCLASS's proposed requirements, is under review at the Office of the Secretary of Defense, he said.

He expects to release an initial request for proposals in early 2016, with a contract award in early 2017, he added.