i used to believe that ww2 aircraft were simpler machinery. however as i had read the design and production stories of various prominent aircraft, i dont hold that misconception anymore.
illogical and ahistorical.
sweeping assumptions based on a few extremely badly executed bombing missions in european theater on germany can not be taken as a measure of realism to reflect on the game.
.
The reason the focus is on Germany is because that is the theater with the most concentration of bombing as well the air forces there more equal on technology levels. Hard to compare Japan and USSR because of differences not only in technology, but focus and goals of the bombing.
For the game purposes we have to take into account what the numbers would be when it is close to equal on techs, size of air forces, and timeline.
So in the historical example of WW2 the Luftwaffe started having issues defending German airspace in 44. Sure there were some problems before then but the real loss of air power was not until then. So for the numbers I proposed it is just looking at average losses for a couple bomber groups and fighter groups on opposing sides over the course of 1943. The difficulty is of course the Allies bombing campaign wasn't up to full swing at that point and also many things were still being learned about formation flying, night vs day missions etc so it is not going to be a completely accurate snap shot even controlling for as much as possible the isolated 1 time occurrence factors.
The important point in the game is to simulate the feeling of the war strategically which to me seems to come down to attrition of pilots, resources allocated, and the doctrines involved and used or not used.
Since IC is much more flexible and easy to gain and maintain in game than in real life I think the % losses of units should be a bit higher in the game than exact outcome of history.