.
Funny, I have always thought otherwise and found the ability for forces engaged in an engagement skirmish to destroy all available support artillery muy muy estupido.
Even though I really hate this kind of argument I would also seriously doubt lightning fast counter-battery fire (like you can have in the wargame serie) was available during WW2.
In wargame/wargame-like games it would be turbo-cancer. The only thing you would be able to do vs. offmap artillery is to be somewhere else when the shells hit.
As for airplanes... really? You can shoot those down, sometimes even before they drop their bombs. Unless you can shoot down artillery shells or somehow blow up the guns, there's no way to compare the two.