Despite the anti-Concorde "industry" in the U.S.A. and elsewhere, McDonnell Douglas are continuing studies of an AST (advanced supersonic transport) designed to carry 237 passengers up to 4.400 naut. miles at a speed of Mach 2.2. As shown by this artist's impression, the aircraft has a NASA-designed "arrow" wing

Although Boeing was successful, in 1966, in winning the design competition for a supersonic transport, its design was far from final definition. At the time of selection, the Boeing 733 had variable geometry (left) but this concept gave way to a fixed delta (right) before the whole project was cancelled.

The projected Boeing 733 supersonic transport with variable-sweep wings

The projected Lockheed Model 2000 supersonic transport