The Boeing 7E7 was announced on 29th January 2003 following the cancellation of the Sonic Cruiser. The aircraft was renamed the Boeing 787 in 2005. This important design marked a major shift in technology for Boeing, which aimed for maximum fuel efficiency in a number of ways. Chief among these was a radical change of construction material, with much of the aircraft being built of carbon fibre reinforced plastic (CFRP). Additionally, the fuselage(機体)was produced as 'barrels' rather than sheets of material, reducing the number of fastenings required. This further increased the weight savings.
(http://www.airliners.net/aircraft-data/boeing-787-8-dreamliner/407)