United Airlines announced that Boeing completed the final assembly of the airline's first 787 Dreamliner Wednesday evening, finishing the first major step in the aircraft's production. United will be the first North American carrier to take a 787 delivery, with plans to introduce the first of 50 Dreamliners into revenue service in 2012.

While in final assembly, the aircraft moved through four factory positions, including the final aircraft body join, landing gear installation, weight-on-wheels testing and installation of interior components and systems. Over the next several months, the aircraft will move to the next phase of completion, which includes final cabin configuration, installation of engines and painting.

Boeing will configure United's first 787 with 36 seats in BusinessFirst, 63 seats in Economy Plus and 120 seats in Economy. The aircraft's use of light-weight composites, together with more electric systems, modern engines and improved aerodynamic design, allows it to fly farther, faster and more efficiently. Customers will experience greater comfort with improved lighting, bigger windows, larger overhead bins, lower cabin altitude and enhanced ventilation systems, among other passenger-friendly features.

United Continental Holdings' subsidiaries Continental and United each ordered 25 Dreamliners. With expanded range capabilities, greater fuel efficiency and superior operating economics, the 787 will allow United to target new long-haul markets and replace older, less-efficient widebody aircraft.