At one point, the Potez 637 was the only modern aircraft equipping the Groupes de Reconnaissance (GOA), which had long been equipped with obsolete aircraft. From November 1939 onwards, the first units to convert to the Potez P.63.11 were each assigned three aircraft. By mid-January 1940, there were 43 Potez 63.11s in service with 12 GOAs. By June 1940, more than 700 reconnaissance Potez 63.11 had been delivered. These aircraft encountered various fates in service: more than 220 were destroyed or abandoned. Despite the addition of extra machine gun armament, aircraft having received either six, eight, or ten machine guns, the Potez 63.11 suffered the heaviest losses of any French type. One factor contributing to the high losses was the near-complete lack of spares, rendering 70 per of all P.63.11 aircraft unserviceable even prior to the German invasion; many aircraft were destroyed on the ground by enemy bombing and strafing attacks, and entire units were wiped out without conducting a single mission.