The Lockheed Martin F-35 Lightning II is a family of single-seat, single-engine, all-weather stealth multirole fighters. The fifth-generation combat aircraft is designed to perform ground attack and air superiority missions. It has three main models: the F-35A conventional takeoff and landing (CTOL) variant, the F-35B short take-off and vertical-landing (STOVL) variant, and the F-35C carrier-based Catapult Assisted Take-Off But Arrested Recovery (CATOBAR) variant. On 31 July 2015, the United States Marines declared ready for deployment the first squadron of F-35B fighters after intensive testing. On 2 August 2016, the U.S. Air Force declared its first squadron of F-35A fighters combat-ready.