ORIGINAL: dtravel
At those altitudes, the settings in the game are in 1,000' increments. So, at best, by shooting directly vertical a defending fighter would be shooting at a target at 1,000' range. Since in reality that effectively never happened (planes flying perfectly vertically up), we're talking about fighters firing at some kind of upward angle. Let's assume its a 45 degree angle, that would mean that the range from the fighter to the bomber is at least 1,400'. What kind of range did WWII fighters have?
Not all increments are in 1000' intervals - at the top and the bottom of the altitudes they don't go by 1000' - i.e. strafing at 100', torpedoes at 200'... similarly, at max altitude you are talking (on occasion) differences of 50' as mentioned before. So, now we are talking ranges of 70 feet, not 1400.
i suspect that the game engine has some "slop factor" built into it now to allow for such things (it didn't before - as i have mentioned, players were quite irate about bombers flying 50' over their fighters).
Also, i have the suspicion (but no definite evidence) that you can have aircraft with operational damage on a mission. IE - your airplane is fine when you take off - the game engine does a die roll and suffers some operational damage. Pilot decides to continue on mission (note analagous situation of flak-damaged aircraft always continue to bomb).
Normally, if there is no opposition, the pilot will complete the mission, return to base and land - and plane will have some damage.
However, suppose the "operationally damaged" aircraft instead meets up with a fighter over the recon target. The plane is much more likely to be shot down (i.e.- a recon plane with some engine trouble is intercepted - the plane is unlikely to be able to fly at max altitude, and so now can be effectively intercepted.)