The Boeing 757 is a twin-engine short-to-medium-range jetliner incorporating advanced technology for exceptional fuel efficiency, low noise levels, increased passenger comfort and top operating performance. The 757 offers other virtues as well, including great versatility by reducing airport congestion. Its seating capacity is between that of the 727 and the 767. Boeing developed the 757 and the 767 concurrently, so both share the same technological advancements in propulsion, aerodynamics, avionics, and materials. Re-contoured sidewall panels became available starting in mid-1987 and is the same as that developed for the Next-Generation 737 family. The new panels provide greater clearance at the head and elbow for passengers and give the entire cabin a more spacious appearance. On Nov. 28, 2005, Boeing concluded the remarkable 23-year run of the 757 passenger airplane by delivering the final one to Shanghai Airlines. The airplane is the 1,050th Boeing 757. The 757 is one of seven commercial models that have sold more than 1,000 airplanes, and more than 1,030 of the 757s are still in service.