What is the timeline for the development of hypersonic jets?
Throughout the 1950s an SST looked possible from a technical standpoint, but it was not clear if it could be made economically viable. There was a good argument for supersonic speeds on medium- and long-range flights at least, where the increased speed and potential good economy once supersonic would offset the tremendous amount of fuel needed to overcome the wave drag. The main advantage appeared to be practical; these designs would be flying at least three times as fast as existing subsonic transports, and would be able to replace three planes in service, and thereby lower costs in terms of manpower and maintenance. A Concorde landing Serious work on SST designs started in the mid-1950s, when the first generation of supersonic fighter aircraft were entering service. In Europe, government-subsidized SST programs quickly settled on the delta wing in most studies, including the Sud Aviation Super-Caravelle and Bristol 223, although Armstrong-Whitworth proposed a more radical design, the
