MD-80 series aircraft, MD-90 is one of the predecessor of Boeing 717, is based on the United States, MacDonald Douglas DC-9-50 developed a new series of twin engine engine in the short haul airliner. October 1977 began to develop, said DC-9 over 80. This new model is to meet the airline for the larger capacity of the short-range aircraft needs, and requirements of aircraft low fuel consumption, high economy, low noise level. MD-80 series compete with Boeing 737. Compared with DC9-50, MD-80 series main improvement is lengthened fuselage, wing span increase, with a more powerful engine and auxiliary power unit advanced (Auxiliary Power Unit), MD80 series aircraft and Boeing 737 and Boeing 777 A320, is 80~90's most popular short haul aircraft. Has stopped production, a total of nearly 1200 production.and 1,2,3 is light.