On 26th December 1975 started regular flights of Tu-144 – a Soviet hypersonic passenger aircraft. It was powered by 4 jet engines Tu-144 and reached maximum speed of 2.5 Ma and could transport 140 passengers. Because of the high working costs the aircrafts were withdrew in 1978. Later on the aircrafts were used in scientific research. The total production of Tu-144 was 16.