For a time, it seemed as though the air travel industry was headed in the direction of more supersonic options. For example, President Ronald Reagan called for a program to develop a hyperspace transport or National Aerospace Plane capable of going from New York to Tokyo in two hours.
Such planes would have to enter outer space in a suborbital flight. They would have to develop the air-breathing rocket engines necessary to achieve the appropriate speeds and deal with the intense heat of re-entry, much like the space shuttle.
However, none of these options ever became commercially viable, making the Concorde and the the Tu-144 the only SSTs that made commercial flights. For more information on SSTs and related topics, check out the links on the next page.