The poster above, produced by United States of America Vietnam War Commemoration, depicts the service patches of the major USAF organizations that participated in Vietnam war.
The Air Force Historical study: Air Force Units in South Vietnam, 1965-1973, was compiled by Colonel John Schlight, Office of Air Force History, 1980. The list is in chronological order by date beginning in June 1965 and ending in March 1973. The list is then in order by location, with a list of units assigned to that location.