Boeing 2707 SSTBoeing SST airplane model. The Boeing 2707 was the first American supersonic transport project. After winning a competition for a government funded contract to build an American SST, Boeing began development at its facilities in Seattle, Washington. The design emerged as a large aircraft with seating for 250 to 300 passengers and cruise speeds of approximately Mach 3. It was intended to be much larger and faster than preceding SST designs such as