The South Pacific air ferry route was initially established in the 1920s to ferry United States Army Air Service aircraft to the Philippines. As the Japanese threat in the Far East increased in 1940, General Douglas MacArthur planned that in the event of war, the United States Army Air Corps would play a major role in defending the Philippines. The reinforcement by the Air Corps of forces in the Philippines, and later Allied forces in Australia, became the basis for developing the South Pacific air ferry route used during World War II.
After the Pearl Harbor Attack in December 1941, the US Air Transport Command pioneered and established scheduled air service to virtually all areas of the Pacific. Japanese mandated islands – formerly unfamiliar to the outside world and islands rarely visited before the war – became important air terminals and way stations along the ATC routes in the Pacific.
After the United States' entry into the Pacific War, the only air service to the Orient was operated by Pan American Airways, while normal shipping lanes were cut off by the Japanese. This necessitated the establishment of new routes, which would skirt the area west of the Hawaiian Islands and north of Australia. In response to this need, ATC inaugurated a trans-Pacific cargo and passenger service through Canton Island, the Fiji Islands, and New Caledonia to Australia. As the war progressed with forward movements of the allied forces transport service was expanded to support the combat operations. New routes were established to include the Solomon Islands, New Guinea, the Gilbert and Marshall Islands, the Marianas, the Philippines, and the Ryukyu island chain. Eventually ATC routes operated into Occupied Japan and connected to the ATC India-China Wing at Kunming Airport, China.