Boeing 737

Originally developed as a narrow-body, short-to-medium range commercial jet transport aircraft, more Boeing 737 aircraft have been produced than any other commercial jet airliner. Its first version, the 737-100, went into service in 1967; it has been in incremental improvement since then, and now is in the "737 new generation", with slightly longer aircraft with extensive wing, engine, and other efficiency improvements. It is the basis for the P-8 Poseidon, developed by the U.S. Navy as a maritime patrol aircraft, and has been adapted for a variety of other military applications, such as the "Wedgetail 737" airborne warning and control system first developed for Turkey. As well as commercial passenger versions, there are civilian cargo and executive transport versions; some types are convertible between freighter and passenger configurations.