here is the video (2 parts):
here you can see not even a pershing can drive over it, and after it is destroyed you can still not drive over it. with attack ground you can shoot over it.
http://www.xfire.com/video/21ec55/however, in part 2 you can see the atg cannot shoot at the building(with attack move) if the glider is blocking his shot:
http://www.xfire.com/video/21ec58/remove gliders, or is it possible to replace them with the commando glider wrecks?