Complex sentence: He was also an aviator during the Second World War, assigned to the Free French 342 "Lorraine" bomber Squadron of the Royal Air Force, with Romain Gary, who was also a talented French novelist.
Split into simpler sentences: He was also an aviator during the Second World War, assigned to the Free French Bomb. Squadron "Lorraine" known as No.342 Squadron in the Royal Air Force with Romain Gary who was also a talented French novelist.