The Sonic Cruiser, by comparison, would not only carry a similar number of passengers as the Boeing 767, but would also have similar per-seat economics, in addition to the huge range.

Boeing decided to build a long-haul plane for them that would set new standards in efficiency. "In the late 1990s, Boeing was working on a design called the Sonic Cruiser," explains aviation ...

In 2001, Boeing scrapped its plans for a 747 jumbo jet called the 747X, instead focusing attention on a new proposal to build a jet that would travel near the speed of sound, called the Sonic Cruiser.

After dropping its unconventional Sonic Cruiser project, Boeing announced the conventional 7E7 on January 29, 2003, which focused largely on efficiency.