In the period from the end of 1937 to 1940 the Soviet Union was the primary supplier of military aircraft to the Chinese Air Force, supplying 536 fighter planes; some of the planes were flown by Soviet volunteer military pilots sent to China.
In the period from the end of 1937 to 1940 the Soviet Union was the primary supplier of military aircraft to the Chinese Air Force, supplying 563 fighter planes and 322 bombers, a total of 1285 planes. Some of the planes were flown by Soviet volunteer military pilots sent to China.