The Douglas DF was a commercial flying boat built by Douglas Aircraft Company and which first flew on 24 September 1936. It could accommodate 32 passengers, or 16 in sleeper cabins, and was the last flying boat built by the company. Despite acceptable handling and performance within design specifications, no commercial orders were forthcoming and faced with no domestic market for aircraft already built, the company obtained export permits for them. The first two production aircraft were sold to Japan, ostensibly for commercial airline use, however one of them was dismantled, reverse-engineered and formed the basis for the development of the Kawanishi H8K. The second one was lost on a survey flight in 1938. The second production pair were sold (as DF-195's) to the Soviet Union and after winterizing, were disassembled and transported to Russia via ship, where they were operated as transports by Aeroflot.