Background

During the late 1990s, Boeing began considering replacement aircraft programs as sales for the 767 and Boeing 747-400 slowed. The company proposed two new aircraft, the 747X, which would have lengthened the 747-400 and improved efficiency, and the Sonic Cruiser, which would have achieved 15% higher speeds (approximately Mach 0.98) while burning fuel at the same rate as the existing 767.^[16] Market interest for the 747X was tepid, but the Sonic Cruiser had brighter prospects. Several major airlines in the United States, including Continental Airlines, initially showed enthusiasm for the Sonic Cruiser concept, although they also expressed concerns about the operating cost.^[17]

Earlier proposed design configuration of the Boeing 7E7.

The global airline market was disrupted by the September 11, 2001 attacks and increased petroleum prices, making airlines more interested in efficiency than speed. The worst-affected airlines, those in the United States, had been considered the most likely customers of the Sonic Cruiser, and thus Boeing officially cancelled the Sonic Cruiser on December 20, 2002. Changing course, the company announced an alternative product using Sonic Cruiser technology in a more conventional configuration, the 7E7, on January 29, 2003.^[8][18] The emphasis on a smaller midsize twinjet rather than a large 747-size aircraft represented a shift from hub-and-spoke theory towards the point-to-point theory,^[19] in response to analysis of focus groups.^[20]

The replacement for the Sonic Cruiser project was dubbed the "7E7"^[21] (with a development code name of "Y2"). Technology from the Sonic Cruiser and 7E7 was to be used as part of Boeing's project to replace its entire airliner product line, an endeavor called the Yellowstone Project (of which the 7E7 became the first stage).^[22] Early concept images of the 7E7 included rakish cockpit windows, a dropped nose and a distinctive "shark-fin" tail.^[23]The "E" was said to stand for various things, such as "efficiency" or "environmentally friendly"; however, in the end, Boeing said that it merely stood for "Eight".^[8] In July 2003, a public naming competition was held for the 7E7, for which out of 500,000 votes cast online the winning title was Dreamliner.^[24] Other names in the pool included eLiner,Global Cruiser and Stratoclimber.^[25]