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. This model saw military service during and after World War II in a number of versions including the United States Army Air Forces (USAAF) C-45 Expeditor, AT-7 Navigator, AT-11 Kansan; and for the United States Navy (USN), UC-45J Navigator and the SNB-1 Kansan.
The Beech 18 is the most modified U.S.-certified aircraft design, with over 200 Federal Aviation Administration (FAA) approved Supplemental Type Certificates (STCs) on record for the aircraft.
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, gun- and drug-smuggling, 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.