I was considering of writing thread like this too...
Theres not really any sense why planes can see tank icon but vehicles cant see vehicle icons, at least, planes can see your tank from over 8000 yards away as BIG dot in the ground.. that does NOT need icons.
Though, my wish would be to hide that dot for the vehicles until more realistic range..
Other idea would be to modify those different land layers so that forrest ground layer would totally hide tank from aircrafts (very hard to see tank through thick forrest!)
and then make it more visible on open fields.