Boeing Sonic Cruiser

The Boeing Sonic Cruiser was a subsonic concept airplane proposed by Boeing Commercial Airplanes in 2001.

The Sonic Cruiser was proposed shortly after the launch of the A380 by rival Airbus. Instead of the A380's massive capacity, requiring a hub and spoke model of operation, the Sonic Cruiser was designed for rapid point-to-point connections for only 250 passengers. With delta wings and flying just short of the speed of sound at 0.95 Mach (about 1010 km/h or 627 mph at altitude), the Sonic Cruiser promised 20% faster speed than conventional airplanes without the noise pollution caused by supersonic Concorde's sonic boom.

However, according to Boeing's own estimates the Sonic Cruiser would also burn 15-20% more fuel for the same trip than conventional aircraft. Most airlines favored lower operating costs over a marginal increase in speed, and the project did not attract the interest Boeing had been hoping for. The Sonic Cruiser project was eventually abandoned in favor of the slower but fuel-efficient Boeing 7E7 Dreamliner.

The Sonic Cruiser was publicly proposed shortly after Boeing withdrew its advanced 747 derivatives from competition with the Airbus 380 when no airline interest was forthcoming. Because of this, it was speculated that the Sonic Cruiser was not a serious proposal, but merely camouflage to disguise the defeat of the 747 derivative concept and make Boeing seem still competitive. The subsequent withdrawal of the project when a more realistic alternative was developed (the 7E7) lends some credence to the speculation.