Editing Boeing 757 (section)

===Background===
In the early 1970s, following the launch of the first wide-body airliner, the [[Boeing 747|747]], [[Boeing]] began considering further developments of its narrow-body [[Boeing 727|727]].<ref name="norris143">{{harvnb|Norris|Wagner|1998|pp=143–45.}}</ref> Designed for short and medium length routes,<ref>{{harvnb|Eden|2008|p=72.}}</ref> the [[trijet]] was the best-selling jetliner of the 1960s and a mainstay of the U.S. domestic airline market.<ref name=norris143/><ref name="norris12">{{harvnb|Norris|Wagner|1999|p=12.}}</ref> Studies focused on improving the 189-seat {{nowrap|727-200}}, the most successful variant.<ref name=norris144/> Two approaches were considered: a stretched 727 (to be designated 727-300), and an all-new aircraft code-named 7N7.<ref name="norris144">{{harvnb|Norris|Wagner|1998|p=144.}}</ref> The former was a cheaper derivative using the 727's existing technology and tail-mounted engine configuration,<ref name=norris144/> while the latter was a twin-engine aircraft which made use of new materials and improvements to propulsion technology which had become available in the civil aerospace industry.<ref name=norris20/>

[[File:Boeing 757-200 Farnborough 1982 Fitzgerald.jpg|thumb|The 7N7 made its [[Farnborough Airshow]] debut in 1982 as the 757-200.|alt=Side view of silver twin-engine jet taxiing on runway, with deployed flaps and "757" markings on tail.]]
[[United Airlines]] provided input for the proposed 727-300, which Boeing was poised to launch in late 1975,<ref name=norris144/> but lost interest after examining development studies for the 7N7.<ref name=norris144/> Although the {{nowrap|727-300}} was offered to [[Braniff International Airways]] and other carriers, customer interest remained insufficient for further development.<ref name=norris143/> Instead, airlines were drawn to the [[High-bypass turbofan|high-bypass-ratio turbofan]] engines, new flight deck technologies, lower weight, improved [[aerodynamics]], and reduced operating cost promised by the 7N7.<ref name=norris144/><ref name=norris20/> These features were also included in a parallel development effort for a new mid-size wide-body airliner, code-named 7X7, which became the 767.<ref name="norris18">{{harvnb|Norris|Wagner|1999|pp=18–19.}}</ref> Work on both proposals accelerated as a result of the airline industry upturn in the late 1970s.<ref name=norris143/><ref name="davies103">{{harvnb|Davies|2000|p=103.}}</ref>

By 1978, development studies focused on two variants: a {{nowrap|7N7-100}} with seating for 160, and a {{nowrap|7N7-200}} with room for over 180 seats.<ref name="norris20">{{harvnb|Norris|Wagner|1999|pp=19–20.}}</ref> New features included a redesigned wing, under-wing engines, and lighter materials, while the forward fuselage, cockpit layout, and [[T-tail]] configuration were retained from the 727.<ref name="norris147">{{harvnb|Norris|Wagner|1998|pp=145–47.}}</ref> Boeing planned for the aircraft to offer the lowest fuel burn per passenger-kilometer of any narrow-body airliner.<ref name="eden98">{{harvnb|Eden|2008|p=98.}}</ref> On August 31, 1978, Eastern Air Lines and British Airways became the first carriers to publicly commit to the 7N7 when they announced launch orders totaling 40 aircraft for the {{nowrap|7N7-200}} version.<ref name=norris20/><ref name=eden98/> These orders were signed in March 1979, when Boeing officially designated the aircraft as the 757.<ref name=norris20/> The shorter {{nowrap|757-100}} did not receive any orders and was dropped; 737s later fulfilled its envisioned role.<ref name="norris95">{{harvnb|Norris|Wagner|1999|pp=95–96.}}</ref>