From some posts, this issue has apparently been discussed before, so I appologize for beating a dead horse - but hey, it doesn't hurt the horse.
To me, the specific issue of how the radar functions is a piece of a bigger question of just what AH is? If it's a combat flight simulator then it should be a representation of a system = in this case air/ground combat during a the 1941-1945 time period. IMHO, this type of simulation should generally represent what was actually going on. That means simulating the actual capabilities of the aircraft/vehicles and support - including radar capabilities.
Fighters didn't have radar (or at least not until late in the war), they had ground controllers vectoring them to the approximate position of contacts or other pilots on patrol calling positions. There was not total coverage of all friendly territory as we have here. Others suggested AI ground control should be modeled in a seperate text buffer - I would very much like to see that. Radar, if desired for game play should only be available while a pilot is on the ground (from tower).
The current all seeing radar does make it easier to coordinate and deal with enemy planes, but that's not simulating the historical action. I'm not suggesting it provides complete SA, but it is greatly enhanced. For example, if you see a distant contact, all you have to do is look at the map to determine if its friend or foe. All is required then is to determine if you're at advantage or not and how you want to handle it.
But don't you think it's possible that limiting the radar to more realistic (for the time period) would encourage more cooperation and teamwork between fighter groups, jabo and bomber flights? Think about it for a minute. Don't those periods when radar is down highten the excitement of running into enemy aircraft? Are you going to be at advantage or disadvantage, will you have to call for help, fight or flee?
Not only do we have hightened SA, but the capability to leap across from on side of the map to the other to defend a base. I would prefer that all be limited to travelling there (by plane or vehicle). How realilstic is that?
If the intent of AH is simply a ACM contest as one post noted (and by extension just a FFA), why bother with seperate countries, squads/wingmen, variable fighter loadouts, bombers and ground vehicles in the MA? FFA can be flown in H2H.