The Boeing 737 twinjet stands out as the most produced jet airliner. The design phase for the new twinjet was different from Boeing's previous commercial jetliners. The upcoming Boeing 777X-9 twinjet is approaching the capacity of the earlier Boeing 747. Airbus had demand for an aircraft smaller than the A300, the first Twinjet wide-body. The first wide-body twinjet, the Airbus A300, entered service in 1974. Advanced Composite Cargo Aircraft (ACCA) is an experimental twinjet transport aircraft. The Northrop T-38 Talon is a two-seat, twinjet supersonic jet trainer. A twinjet or twin-engine jet is a jet aircraft powered by two engines. The availability of powerful and reliable turbofans allowed a twinjet to be considered. On 12 March 1987, Airbus received the first orders for the twinjet. The Hawker 400 is a small twinjet corporate aircraft. The Hawker 800 is a mid-size twinjet corporate aircraft. By 1988, the 767-X had evolved into an all-new twinjet, which revived the 777 designation. The British Aerospace 125 is a twinjet mid-size business jet. Fuel efficiency of a twinjet is better than that of aircraft with more engines.