I can see all the buildings just fine, its just that they don't have textures most of the time.
Heres what happened exactly:
1. Load default Cessna 182 into KORD scenery. Everything is there, but there is no textures. So I give it a minute cause I know its a big airport and all.
2. Textures load up and stay loaded for about 15 seconds.
3. Game freezes up for 30 seconds.
4. When game un-freezes, all the textures are missing.
5. Wait 30 more seconds, textures still missing. Soon after, textures appear one by one very fast.
6. Repeat steps 2-5 again.
7. Demo runs out.
The same thing happens with KLAS and KJFK but alot less often.
Do you want a screenshot?