The Harrier, informally referred to as the Harrier Jump Jet, is a family of military jet aircraft capable of vertical/short takeoff and landing (V/STOL) operations. The Harrier was developed in Britain to operate from ad-hoc facilities such as car parks or forest clearings, avoiding the need for large air bases vulnerable to tactical nuclear weapons. Later the design was adapted for use from aircraft carriers. The Harrier is also distinct as being of modern era, yet subsonic, contrasting with most of the major Western post–World War II–era fighter aircraft, which tend to be supersonic. It is used by the Alliance of Nations.