[1] In 1945 Pan American World Airways requested a DC-7, a civil version of the Douglas C-74 Globemaster military transport.

[3] American Airlines revived the designation when they requested an aircraft that could fly across the United States coast-to-coast non-stop in about eight hours.

Some blamed this on the need for high-power settings to meet the national schedules, causing overheating and failure of the engines' power recovery turbines.

[8] The DC-7 was followed by the DC-7B with slightly more power and optional fuel tanks over the wing in the rear of the engine nacelles (selected by Pan Am and South African Airways), each carrying 220 US gallons (183 imp gal; 833 L).

Pan Am's DC-7Bs started flying transatlantic in summer 1955, scheduled 1 hr 45 min faster than the Super Stratocruiser from New York to London or Paris.

European carriers could not take advantage of the small range-increase of the early DC-7, so Douglas released an extended-range variant, the DC-7C (Seven Seas) in 1956.

Two 5 ft (1.5 m) wingroot inserts added fuel capacity, reduced interference drag and made the cabin quieter by moving the engines farther outboard; the optional nacelle fuel tanks previously seen on Pan American's and South African's DC-7Bs were made standard.

The Lockheed Super Constellation and DC-7B that appeared in 1955 could occasionally make the westward trip, but in summer 1956 Pan Am's DC-7C finally started doing it fairly reliably.

The DC-7C sold better than its rival, the Lockheed L-1649A Starliner, which entered service a year later,[9] but sales were cut short by the arrival of Boeing 707 and Douglas DC-8 jets in 1958–60.