The Fokker F.25 Promotor, first flown in 1946, was a single-engined, twin-boomed, four-passenger monoplane with a pusher engine mounted at the rear of a central nacelle. It was of wooden construction and has fitted with a retractable nosewheel undercarriage. One feature of the design was that instead of a 2 + 2 seating, the pilot sat in front to the left, and all three passengers were on a bench seat to the rear of him. Alternatively, when being used as an air ambulance aircraft, it could carry a patient on a stretcher, which was loaded through a hatch in the aircraft's nose. The F.25 was evocative of the pre-war G.I design. The F.25 was based upon the design of the Difoga 421 aircraft, home-built and -designed secretly during World War II by Frits Diepen, a Ford garage owner from Tilburg, the Netherlands. His intention was to escape from German-occupied Europe to Britain using this aircraft that was powered by a Ford V-8.
Although 20 F.25 aircraft were constructed, sales were disappointing for the same reason that thwarted the sales prospects of so many American post-war designs. A newly built aircraft could not compete in cost with the thousands of surplus aircraft on the market in the years following the war.