Regarding the visibility of tanks:
Having viewed tank battles up close and personal (as an observer at Ft. Irwin), there are really two sides the tank visibility problem.
A tank standing still with even a moderate camoflage that matches the terrain is very difficult to see from the air. Without optical aids (binoculars, FLIR, etc.), a tank is fairly safe from being picked out. However, once it starts to move you can see it from many miles away. In a dry, treeless, sandy or dusty ground environment you can see movement of tanks well beyond normal visual ranges because of the dirt plumes they kick up. Even without the plumes, the eye is sensitive to movement and can pick out that movement at great distances. Of course even a tank with good camoflage becomes quite visible, if only for a moment, if it fires it main weapon.
So, I'll throw out an idea:
Make a ground vehicle more difficult to spot if it is not moving.
MiG