A supersonic transport (SST) is a civil aircraft designed to transport passengers at speeds greater than the speed of sound. The only supersonic civilian aircraft to see service were the Soviet produced Tupolev Tu-144 which first flew in 1968 and was retired in 1997; and the Franco-British produced Concorde, which first flew in 1969 and remained in service until 2003. Since 2003, there have been no supersonic civilian aircraft in service.