Pilots with Marine Fighter Attack Squadron 121 exit F-35B Lightning II’s after conducting training during exercise Red Flag 16-3 at Nellis Air Force Base, Nevada, July 20, 2016. This is the first time that the fifth generation fighter has participated in the multiservice air-to-air combat training exercise. - Pilots with Marine Fighter Attack Squadron 121 exit F-35B Lightning II’s after conducting training during exercise Red Flag 16-3 at Nellis Air Force Base, Nevada, July 20, 2016. This is the first time that the fifth generation fighter has participated in the multiservice air-to-air combat training exercise.