I see this at all altitudes. Anything overlayed on the ground, keeps appearing/disappearing:
roads,
airbases,
cities,
coastlines,
etc.
I have to remember what the orientation of runways is, as they are generally not visible untill I'm on short final. When trying to bomb the cities, I just have to guess where buildings are, and hope they're still up. I can handle the other bugs I've seen, but this is a real playability problem for those using ATI cards. If video drivers or settings, or system configuration will help, let me know. This really detracts from the game experience and is a genuine bug.
--Peregrine.