GV is a part of the game, however getting kills against a flying plane with main gun did never happened during ww2.
The reason is works here is because the tank is one nervous system, not 4 or 5 like in a real tank. A gunner with his very limited FOV could not track a moving plane the commander or loader spotted.
Also to be that effective the commander/gunner have to sit half upper body exposed to gunfire.
As for those Wirbies, they are just too effective, with computer ranging sights no-one had IRL, and very long effective range.
Same go for bomb****ing with outside view, it did not happened in RL and it should not happen here.
Tank should have a outside/inside switch for visibility/vulnerability, Wirbies should have a reduced effective max range, and bombing from F3 view should be stopped.