[Mobhack]

Aircraft fly at an altitude Z which is above the contours, trees, buildings etc. About equivalent to Helo High, or a little more.

Level bombers though fly at an altitude too high for smaller AAA, or some MANPADS to engage. But level bombers are rather irrelevant.

Helo Low altitude helos are hidden by trees, a contour or a building. Landed helos are on the ground, of course.

Any actual figure for Z is merely notional. This is a game of ground warfare - therefore details of what "the crabs" are actually up to are irrelevant to you as a commander, as long as they deliver the ordnance.

Andy