Douglas DC-4 DC-4A

DC-4A is the designation under which C-54 Skymasters were certified for civil use. In late 1945 several hundred C-54s were surplus to US military requirements and were converted for airline operation, many at Douglas's own plants, and then sold to airlines around the world.

The effect was immediate: by January 1946 Pan American was flying its Skymasters on scheduled transatlantic services to Europe and beyond, and on 6 June 1946 it opened trans-Pacific schedules from San Francisco to Auckland. That flood of cheap, available aircraft is why Douglas sold only 79 new civil DC-4s — and also why the type kept flying for decades with smaller operators.