It was also intended to be fuel efficient, carry 300 passengers, and allow customers to buy tickets at a price only slightly higher than those of subsonic aircraft.

While the Concorde and Tu-144 programs both yielded production aircraft, neither was produced in sufficient numbers to pay for their development costs.

In 1989, NASA and industry partners began investigating the feasibility of radically higher-speed passenger aircraft.

Sonic boom mitigation technologies were tested using an SR-71 Blackbird,[5] but were considered to be economically unviable; instead, HSCT would be limited to subsonic speeds over land.

Two F-16XLs were used to test supersonic laminar flow control and to validate advanced CFD design methods.