Moynet volunteered for military service on 26 December 1939, becoming a fighter pilot.

As a member of the Normandie-Niémen squadron he recorded 115 aerial missions accounting for 150 wartime flying hours.

He also did work for Matra and even gave his name to the Moynet M.360 Jupiter, a small propeller driven aircraft.

Moynet was also instrumental in Matra’s move into the automobile business, being responsible for the conception and development in 1968 of a Sports prototype which was developed to achieve a class win (1600–2000 cc) at Le Mans in 1975 (drivers: Michèle Mouton, Marianne Hoepfner and Christine Dacremont).

Relocating to the south of the country, he was elected mayor of the small town of Biot in 1971, holding office for a full term until 1977.