In August 1961 he joined covert operations in what would become the 1st Air Commando Wing, remaining there until 1965. As part of Operation Farm Gate, the wing was the first American aviation unit assigned to Vietnam. Secord flew over 200 combat missions between March 1962 to January 1963, flying AT-28s. One of the Vietnamese pilots he met during this assignment was Nguyen Cao Ky, later the president of Vietnam. Another new acquaintance there was Brigadier General Harry "Heinie" Aderholt. Also during this time, Secord was temporarily assigned to the Imperial Iranian Air Force as an adviser (January to July 1963, January to May 1964, January to March 1965).