How it started
Before Air Micronesia
The islands of the Trust Territory of the Pacific Islands (TTPI) were, before World War II, those of the pre-World War II South Seas Mandate of the Empire of Japan. From 1934 through 1941, the empire developed a commercial airline network in the mandate, though it was little used by Micronesians. After World War II, the TTPI was initially the responsibility of the US Navy, which provided civilian air transport with Martin PBM-5A Mariner and Douglas R4D (naval DC-3) aircraft. The PBM required JATO to take off at Yap.
As of July 1951, responsibility for the TTPI transferred to the Department of the Interior. From that date through May 1968, the TTPI ran its own airline, Trust Territory Air Service, using contractors to fly the aircraft. Contractors were responsible for flying aircraft and line maintenance; the TTPI owned the aircraft and took care of everything else. The contractors were:
Transocean Air Lines from 1951 through its collapse in 1960. Transocean initially flew PBY Catalina amphibious aircraft, before transitioning to Grumman SA-16 amphibians.
Pan American World Airways from 1960 through 1968. Pan Am took over the SA-16s and added Douglas DC-4s. The aircraft were branded "Trust Territory" (see photo).
Startup
From Wikipedia’s article on Continental Micronesia, shared under CC BY-SA 4.0.2