The Avion de Transport Supersonique Futur (ATSF) also known as Alliance, was a concept design for supersonic transport developed by British Aerospace and Aérospatiale together. The aircraft was to be based on the experience learned from the supersonic Concorde, and was to fly at a top speed of roughly Mach 2. Preliminary designs were produced, with some wind-tunnel testing of small-scale models, but development apparently stalled in the early 2000s.