FRom Wiki
Military service
During World War II, McMahon was trained as a United States Marines fighter pilot and also served as a flight instructor and test pilot. He was discharged in 1946, remaining in the reserves.[3]
After college, McMahon was re-activated into active Marine duty. He was sent to Korea in February 1953. He flew unarmed O-1E Bird Dogs on eighty-five tactical air control and artillery spotting missions. He remained in the Marine reserves, retiring with the rank of Colonel in 1966 and was then commissioned as a Brigadier General in the California Air National Guard.
Several of his ancestors, including the Marquis d’Equilly, also had long and distinguished military careers. Patrice MacMahon, duc de Magenta was a Marshal of armies in France, serving under Napoleon III, and later President. McMahon once asserted to Johnny Carson that mayonnaise was originally named Macmahonnaise in honor of this ancestor, referring to him as the Comte de MacMahon.[4] In his autobiography, McMahon said that it was his father who told him of this relationship and he went on to suggest that he was not certain of the truth of the story.[5]