Throughout the 1960s and 1970s the C-1 Trader carried mail and supplies to aircraft carriers on station in the Pacific Ocean during the Vietnam War and also served as a trainer for all-weather carrier operations. Over its production life 87 C-1 Traders were built, of which four were converted into EC-1A Tracer electronic countermeasures aircraft. The last C-1 was retired from USN service in 1988; it was the second-to-last radial-engine aircraft in U.S military service (The last C-131 wasn't retired until 1990). As of 2010, approximately ten were still airworthy in civil hands, operating as warbirds.
