Stratostar was a proposed aircraft design from the 1950s that aimed to be the world's first practical airliner capable of flying at supersonic speeds. The design called for a large delta-wing aircraft that could carry up to 300 passengers at speeds over Mach 1.5 using turbojet engines. However, the Stratostar project was ultimately cancelled in 1960 due to technical challenges and rising costs associated with developing an aircraft of this scale that could fly supersonically.