An F-35B Lightning II with Marine Fighter Attack Squadron (VMFA) 121 takes off from Red Beach on Marine Corps Base Camp Pendleton, Calif., Dec. 10. This is the first time that the F-35 conducted close air support missions in support of exercise Steel Knight. (U.S. Marine Corps photo by Sgt. Brian Marion/Released) - An F-35B Lightning II with Marine Fighter Attack Squadron (VMFA) 121 takes off from Red Beach on Marine Corps Base Camp Pendleton, Calif., Dec. 10. This is the first time that the F-35 conducted close air support missions in support of exercise Steel Knight. (U.S. Marine Corps photo by Sgt. Brian Marion/Released)

An F-35B Lightning II with Marine Fighter Attack Squadron 121, based out of Marine Corps Air Station Yuma, Ariz., performs a vertical landing as part of required flying field carrier landing practices (FCLP) at the station’s auxiliary landing field, Monday, April 27, 2015. The landing field simulates the flight deck of an aircraft carrier to prepare pilots for landing and taking off at sea. (Official Marine Corps photo by Cpl. Travis Gershaneck/Released) - An F-35B Lightning II with Marine Fighter Attack Squadron 121, based out of Marine Corps Air Station Yuma, Ariz., performs a vertical landing as part of required flying field carrier landing practices (FCLP) at the station’s auxiliary landing field, Monday, April 27, 2015. The landing field simulates the flight deck of an aircraft carrier to prepare pilots for landing and taking off at sea. (Official Marine Corps photo by Cpl. Travis Gershaneck/Released)

An F-35B Lightning II, with Marine Fighter Attack Squadron (VMFA) 121 “Green Knights,” refuels on the flight line aboard Marine Corps Air Station Yuma, Arizona, Aug. 18. The Lightning II is scheduled to show off its capabilities during demonstrations at the 2014 Miramar Air Show, Oct. 3-5. - An F-35B Lightning II, with Marine Fighter Attack Squadron (VMFA) 121 “Green Knights,” refuels on the flight line aboard Marine Corps Air Station Yuma, Arizona, Aug. 18. The Lightning II is scheduled to show off its capabilities during demonstrations at the 2014 Miramar Air Show, Oct. 3-5.