Airborne radar was not used in that way in WWII. There was no WWII equivilent of an AWAC aircraft. Airborne radar in WWII was used for three purposes. 1) To hunt enemy aircraft in conditions that made visual hunting impractical, mostly at night. 2) To detect enemy aircraft coming into attack position, though in some cases, most notably Monica on Lancs and Halibags, this tail warning radar was actually homed in on my the Germans. 3) Air to surface radar to help bomb aimers and navigators with their jobs in conditions when the ground is not visible. It may also have been used to find ships from the air, I do not know about that one way or another.