Marines perform a weapons functional test on an F-35B Lightning II aircraft during Exercise Steel Knight at Marine Corps Air Ground Combat Center Twentynine Palms, California, Dec. 10, 2015. The F-35B is a single seat, single engine stealth multi-role fighter bringing the Marine Corps into a whole new generation of aircraft. Exercise Steel Knight allowed for Marine Fighter Attack Squadron 121 and Marine Operational and Test Evaluation Squadron 22 to train on integrating the F-35B and find its place in the Marine Air Ground Task Force, while giving the ground forces of 1st Marine Division the ability to become familiar with it. - Marines perform a weapons functional test on an F-35B Lightning II aircraft during Exercise Steel Knight at Marine Corps Air Ground Combat Center Twentynine Palms, California, Dec. 10, 2015. The F-35B is a single seat, single engine stealth multi-role fighter bringing the Marine Corps into a whole new generation of aircraft. Exercise Steel Knight allowed for Marine Fighter Attack Squadron 121 and Marine Operational and Test Evaluation Squadron 22 to train on integrating the F-35B and find its place in the Marine Air Ground Task Force, while giving the ground forces of 1st Marine Division the ability to become familiar with it.

A sailor aboard the USS Wasp (LHD-1) signals to the pilot of an F-35B Lightning II Joint Strike Fighter to land as it arrives for the first phase of operational testing, May 18, 2015. The short take-off, vertical landing capabilities of the F-35B are crucial to the mission of the Marine Corps and necessary for operation aboard a Navy amphibious ship. The aircraft are stationed with Marine Fighter Attack Training Squadron 501, Marine Aircraft Group 31, 2nd Marine Aircraft Wing, Beaufort, South Carolina and Marine Fighter Attack Squadron 121, Marine Aircraft Group 13, 3rd Marine Aircraft Wing, Yuma, Arizona. (U.S. Marine Corps photo by Lance Cpl. Remington Hall/Released) - A sailor aboard the USS Wasp (LHD-1) signals to the pilot of an F-35B Lightning II Joint Strike Fighter to land as it arrives for the first phase of operational testing, May 18, 2015. The short take-off, vertical landing capabilities of the F-35B are crucial to the mission of the Marine Corps and necessary for operation aboard a Navy amphibious ship. The aircraft are stationed with Marine Fighter Attack Training Squadron 501, Marine Aircraft Group 31, 2nd Marine Aircraft Wing, Beaufort, South Carolina and Marine Fighter Attack Squadron 121, Marine Aircraft Group 13, 3rd Marine Aircraft Wing, Yuma, Arizona. (U.S. Marine Corps photo by Lance Cpl. Remington Hall/Released)

A F-35B Lightning II with Marine Operational and Test Evaluation Squadron 22 taxies under a canopy aboard Edwards Air Force Base, Calif., Oct. 9. This is the squadron’s first F-35 Lightning II. - A F-35B Lightning II with Marine Operational and Test Evaluation Squadron 22 taxies under a canopy aboard Edwards Air Force Base, Calif., Oct. 9. This is the squadron’s first F-35 Lightning II.