The story of the Normandie (later, Normandie-Niemen) Escadrilles makes for fascinating reading. Originally recruited by DeGaulle himself, these French pilots flew for the Soviets in Soviet-made aircraft at more than typical risk to themselves. The Germans saw this development as a breach of the French Vichy government’s surrender agreement and made it a policy to execute any French pilots downed in their territory. In addition, family and relatives of the downed pilots were arrested back in France and sent to concentration camps, where few survived.
Despite this threat, the small French unit would wind up with over 30 confirmed aces and a total of 273 enemy aircraft downed by war’s end, making them the second highest scoring aerial unit in the Soviet Union. In addition, no Russian bomber under escort by them was ever lost to enemy action.