Yeah, Bombtaxi's kinda right there, and not just the Russian Front being target-rich, but also the Europe that Hitler intially conquered...none of those countries really had anything to match the, by then, very experienced Luftwaffe....They clobbered Britain pretty hard in the run-up to Dunkirk, but some of our Hurricane pilots were blooded there, and that was the experience that was passed on to new RAF pilots in the run-up for the BoB....
I think if you subtracted all the Luftwaffe fighter pilot kills from before then, that over the period of the BoB onward, the respective kill-rates between the RAF and Luftwaffe, that were on the Continent, you'll find that they're probably similar....They were both fairly evenly matched in combat....The continental Luftwaffe pilots did get R R, I have read of some of their off-duty exploits, plus they got time off for recovery from injury. These guys were the cream of the German Forces, and they were looked-after pretty well, at least until things started to get pretty desperate for Germany.......
In a nutshell, the Luftwaffe and the Japs enjoyed an intial period of total Air Superiority during the start of their respective Wars, and both had built up previous battle-experience before the War kicked-off proper; the Japs in China, and the Luftwaffe from the Spanish Civil War and then 'Blitzkreig Europe', before they started to tackle the Allies.......