The Bell P-59 Airacomet is a single-seat, twin jet-engine fighter aircraft that was designed and built by Bell Aircraft during World War II. It was the first jet produced in the United States. As the British were further along in jet engine development, they donated an engine for the United States to copy in 1941 that became the basis for the General Electric J31 jet engine used by the P-59 a year later. Because the plane was underpowered, the United States Army Air Forces (USAAF) was not impressed by its performance and canceled half of the original order for 100 fighters, using the completed aircraft as trainers. The USAAF would instead go on to select the Lockheed P-80 Shooting Star as its first operational jet fighter. Although no P-59s entered combat, the aircraft paved the way for later generations of U.S. turbojet-powered aircraft.