Don't mistake WWII radar with nowadays AWACs.
In WWII the gathered data of ground radar were forwarded to Situation Rooms or Leitzentralen as the HQ in AH.
If these centers were destroyed, no more information was available.
I would say AH reflects very well the reality.
The airborne radars in WWII were crude and difficult to use.
And the last thing you got, was a picture of the situation around you.
These radars were made for hunting buffs in the night. Mostly they made a narrow, sharp cone in front of the plane.
Some US buffs had navigation radar, which gave an image of the ground below. But they were restricted to this purpose.
If you are deep inside enemy territory, you have to keep your eyes open. There is no need to change this.