Boeing 737s serve markets previously filled by other midsize airliners.
Many 737s serve markets previously filled by 707 , 727 , 757 , DC-9 , and MD-80 / MD-90 airliners , and the aircraft currently competes primarily with the Airbus A320 family.
The Boeing 727 is a midsized , narrow-body three-engined jet aircraft built by Boeing Commercial Airplanes from the early 1960s to 1984.
