Fighter aces in World War II had tremendously varying kill scores, affected as they were by many factors: the pilot's skill level, the performance of the airplane the pilot flew and the planes they flew against, how long they served, their opportunity to meet the enemy in the air (Allied to Axis disproportion), whether they were the formation's leader or a wingman, the standards their air service brought to the awarding of victory credits, et cetera.
Towards the end of the war, the Axis powers had largely exhausted their supply of skilled pilots and the replacements did not have as much opportunity to gain enough experience to be successful.
Additionally, national policies differed; German, Italian, and Japanese[1] pilots tended to return to the cockpit over and over again until they were killed.
[N 1] It is not clear what impact each nation's rules for score crediting have on the counts listed below.
The Italian Air Force did not officially credit victories to individual pilots, but to their unit as a whole.
It is necessary to emphasize that the question of assessing and comparing the success rate of fighters by number of victories is one of the more problematic.
The most reliable is considered the confirmation of the victories in RAF, which based its counts on comparison of testimonials of participants and – if possible – film material.
There were 51 air aces from Austria (3 RAF and 48 Luftwaffe) during the Second World War.
There were more than 25 fighter aces from China during the Second World War, although not all flew for the Allies.
There were 25 fighter aces from the Independent State of Croatia, fighting for the Axis, during the Second World War.
[citation needed] * Jesús A. Villamor * César Basa There were 91 air aces from Poland during the Second World War.
Soviet Union produced the highest scoring allied aces during the Second World War.
See List of World War II aces from the United States.