The DF 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. The second aircraft 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.
Specification/designation of the first two aircraft sold to Japan.
Specification/designation of the second two aircraft sold to the Soviet Union.
Data from Jane's all the World's Aircraft 1937, McDonnell Douglas aircraft since 1920 : Volume I, Biplanes, Triplanes, and Seaplanes, NICO BRAAS COLLECTION, No. 9317. Douglas DF-151
Crew: 3 flight crew + cabin crew
Capacity: up to 32 passengers in four 8-seat compartments