Many planes in AH seem to be a bit too good at high altitude. Take Spits for example, read combat reports from Spit pilots (spit Mk1 in this case) who said that when they were flying at 30k they had to have an extreemly high angle of attack to maintain altitude, this is something that doesn't exist in AH, all planes have a fairly low AoA even at extreem altitudes.
Now I don't mean to moan but in real life a prop will stop working around 30,000ft because the air is so thin, but I was able to climb to 37,000ft in a Zero???? Was I wrong or the game??
You were wrong. Props does in no way stop to work at or about 30,000 feet. The Ta152 and the P47's are good and nice proof of this.
The Ta152 had a cealing of just above 50,000 feet and it had its best speed (using GM1 boost) at 41,000 feet, that's 11k above your stated "max" altitude.
The P47 was also a terrific high alt plane with a cealing well above 30k.
The problem with high altitudes and prop planes is not the prop, it's the engine. At such extreem altitudes the air pressure is lower and thus the engine won't get as much air as should. This is where different boost systems come in, GM1 in the case of the Ta152.
The P47 had a ramjet effect that increased speed aswell I believe.