I was able to reproduce it and, guess what, it's not a problem of the scenery...
I too tried starting a flight from LEVC, then switching to KDFW, and the ground tiles disappeared, depending on the view distance/angle. Then I've tried other airports randomly, and with some the problem appeared just the same, but not with others, without any obvious logic. Note that it wasn't required to start a flight from LEVC. Even starting at KDFW, switching to LEVC and back to KDFW recreates the problem.
Usually, when strange issues or even crashes happens at certain airports only, it might related to AI traffic so, I've switched off AI traffic, and then I could start from LEVC or any other airport then switch to KDFW without any issues.
NOTE, I've WoAI in FS9. Perhaps there's a problem with a model, so I've removed the WoAI traffic.bgl and restored the default one, so I've got MS models instead, then I put traffic back on at 100% and, as expected, no problems whatsoever, even when starting from any of the airports that used to create issues before, they now allow to switch to KDFW when the MS AI models are used.
There's no even need to remove the traffic.bgl to replicate this, you can leave traffic.bgl for the AI pack you have, and put traffic to 100%, then go to LEVC, go back to KDFW, problem appear. Then, put traffic at 0%, go to LEVC again, go back to KDFW, no problem.
The most likely explanation, one of the AI models that come with WoAI that appears at LEVC has a problem (maybe texture-related, but that's just a guess), which triggers a memory corruption or something like that which affects the scenery.
