De Havilland Canada DHC-6 Twin Otter
…States Air Force. Development of the aircraft began in 1964, with the first flight on 20 May 1965. A twin-engine replacement for the single-engine DHC-3 Otter retaining the DHC-3's STOL qualities, its design features included double-slotted trailing-edge flaps and ailerons that work in unison with the flaps…