Derived from the DC-9, the McDonnell Douglas MD-80 is a twin-engine, medium-range, single-aisle commercial jet airplane. It was introduced commercially in October 1980 by Swissair and can seat up to 172 passengers.
Douglas Aircraft developed the DC-9 in the 1960s as a short-range companion to the larger DC-8. The MD-80 was the second generation of the DC-9. It was originally called the DC-9-80 before it was redesignated in July 1983 as a marketing move, to show that McDonnell Douglas had an airliner for the 1980s. The MD-80 features a fuselage about 14 feet longer than the DC-9. The wings were redesigned by adding sections at the wing root and tip for a wing that is 28 percent larger. The cockpit, avionics, aerodynamics and engines were upgraded. It also has a higher maximum take-off weight, greater fuel capacity and longer range than the DC-9.
The MD-80 has been used by airlines around the world. While many airlines have started to retire the aircraft in the 2000s, it is still flown extensively by some, including Delta Air Lines, on domestic routes. Delta is the second largest operator of the MD-80, after American Airlines.