C-118 Liftmaster MATSDouglas C 118 Liftmaster airplane model. The Douglas DC 6 is an aircraft built by the Douglas Aircraft Company from 1946 to 1959. Originally intended as a military transport near the end of World War II, it was reworked after the war to compete with the Lockheed Constellation in the long range piston transport market. More than 700 were built, and many still fly today in cargo, military, and wildfire control roles. The DC 6 was known as the C 118