The long distances across the Atlantic and, especially, Pacific oceans to combat areas indicated a need for a transoceanic heavy-lift military transport aircraft.

[1] Although not produced in large numbers, the C-74 did fill the need for a long-range strategic airlifter, in which capacity the subsequent Douglas C-124 Globemaster II was used by the Air Force for many years.

The Douglas Aircraft Company began studies at their Santa Monica division in early 1942 for a transport capable of fulfilling the global logistical needs of the U.S. military.

This became the Douglas Model 415 and a cost-plus contract worth more than $50 million was signed 25 June 1942 for 50 aircraft and one static test article.

At the time of its first flight, the C-74 was the largest landplane to enter production, with a maximum weight of 172,000 lb (78,000 kg).

Pan American intended to use the 108-passenger aircraft for international travel between New York, Rio de Janeiro, and other cities.

The passenger compartment was to be outfitted with a lounge bar, dining area and sleeping cabins for night flights.

It could carry 125 fully equipped troops, 115 litter patients with their medical attendants, or up to 50,000 lb (22,700 kg) of cargo.

This was due to the fact that the runways at Memphis were not stressed to take the large gross weight of the C-74, resulting in some minor cracking to the concrete surface.

[2] Once in operational use, C-74s began to be used on scheduled MATS overseas routes through the late 1940s and mid-1950s:[8] Additionally, logistic support flights for Strategic Air Command (SAC), and Tactical Air Command (TAC) saw the Globemaster in North Africa, the Middle East, Europe, the Caribbean, and within the United States.

SAC also continued to use the Globemasters to rotate Boeing B-47 Stratojet Medium Bombardment Groups on temporary duty in England and Morocco as part of their REFLEX operation.

The mission was accomplished by having the equipment cut into pieces by welding torch at Rhein-Main and flown aboard the C-74 into Gatow for reassembly.

The fact that the runways in Berlin were not stressed for the airlifter's weight and the aircraft was not compatible with the corridor's scheduling were other factors considered for its withdrawal.

From 1 July–December 1950, the Globemasters logged over 7,000 hours in flights to Hawaii hauling troops and high priority cargo west toward the Korean War and returning eastward with wounded GIs.

These figures, coupled with the fact that, since 1946, the C-74 had flown over six million miles and 31,000 flying hours without a single injury to crewmen or passengers, give testimony to the Globemaster's reliability.

On 1 November 1955, the C-74s were placed in flyable storage at Brookley AFB while the group waited for instructions as to the disposition of the aircraft.

[7] During the first three months of 1956, the 11 remaining C-74s were officially removed from the Military Air Transport Service's inventory and were flown one by one to Davis-Monthan AFB, Arizona for long-term storage and disposition.

Colonel George S. Cassady, who had accepted the first C-74 for the Air Force and who was by then a Brigadier General, was attending a Continental Division Commander's Conference when he learned of the C-74's last flight.

[7] Most of the C-74s in storage at Davis-Monthan AFB were scrapped in 1965, although four ended in civilian hands, mostly owned by Aeronaves de Panama (holding company for "Air Systems").