The Argosy Series 100 first entered service with the American cargo airline Riddle Airlines. Early on, Riddle had expressed interest in the type, having ambitions to use the type to meet contracts to provide logistics support to the United States Air Force (USAF) within the domestic United States. During late 1960, Riddle purchased a batch of seven Argosies for this purpose. However, when Riddle lost the logistics contract during 1962, its Argosies were repossessed by Armstrong Whitworth and subsequently sold onto other airlines, some of which had taken over the contracts previously being served by Riddle.