A supersonic business jet (SSBJ) is a business jet travelling above the speed of sound: a supersonic aircraft. Some manufacturers are designing or have been designing SSBJs, but none are currently available. Usually intended to transport about ten passengers, proposed SSBJs would be about the same size as subsonic business jets.
Only two commercial supersonic transports entered service: the Aérospatiale/British Aerospace Concorde and the Tupolev Tu-144. Both were designed with government subsidies and did not recoup development costs. They had high operating costs and high noise.
Some manufacturers believe these concerns can be addressed at a smaller scale, offering high speed transport for small groups of high-value passengers, executives or heads of state. Current proposals include SAI Quiet Supersonic Transport and Spike S-512. Former proposals include the Aerion SBJ, Aerion AS2, HyperMach SonicStar, Sukhoi-Gulfstream S-21 and Tupolev Tu-444. Several companies, including Gulfstream Aerospace, work on sonic booms-mitigation technologies like the Quiet Spike.