The majority of Caribou production was for military operators, but the type's ruggedness and excellent STOL capabilities also appealed to a select group of commercial users. US certification was awarded on 23 December 1960. AnsettMAL, which operated a single example in the New Guinea highlands, and AMOCO Ecuador were early customers, as was Air America (a CIA front in Southeast Asia during the Vietnam War era for covert operations). Other Caribou entered commercial service after being retired from their military users.