The Beechcraft Model 18, or "Twin Beech", as it was better known, is a 6-11 place, twin-engine, low-wing, conventional-gear aircraft that was manufactured by the Beech Aircraft Corporation of Wichita, Kansas. The aircraft's uses have included aerial spraying, sterile bug release, fish seeding, dry ice cloud seeding, aerial firefighting, airborne mail pick up and drop, ambulance service, numerous movie productions, skydiving, freight, engine test bed, skywriting and banner towing. A number of Model 18s were operated as passenger aircraft; the Model 18 was the first aircraft flown by Philippine Airlines, Asia's first and oldest airline. Many are now in private hands as prized collectibles.

Construction of the Beechcraft Model 18 ended in 1970 with the last, a Model H18, going to Japan Airlines. Beechcraft set a record that still stands today for longest continuous production of a piston engine aircraft. Through the years, 32 variations of the basic design had flown, over 200 improvement modification kits were developed, and almost 8,000 aircraft had been built. Some aircraft were almost unrecognizable as having originated as a Beech 18. In one case the aircraft was modified to a triple tail, tri-gear, hump backed configuration and appeared similar to a miniature Lockheed Constellation.