The McDonnell Douglas MD-80 series are twin-engine, medium-range, single-aisle commercial jet airliners. The MD-80 aircraft were lengthened and updated from the DC-9. The MD-80 series can seat from 130 up to 172 passengers depending on variant and seating arrangement.
The MD-80 series was introduced commercially in October 1980 by Swissair. The MD-80 series was followed into service in modified form by the MD-90 in 1995 and the MD-95/Boeing 717 in 1999.