Was the airport flat?
I’ve noticed this happen and it’s not just that textures don’t load. It’s as if it doesn’t load the airport scenery asset which would also flatten the ground.
If runways and taxi-ways are roller-coasters this is not simply a texture load or render (GPU) issue. It’s that the scenery data which modifies the landscape to be level enough to navigate has not been loaded.
I think being in Devmode can force this to happen (thats the access interface for SDK scenery creation after all)
Outside of devmode it could be file system issue or possibly even CPU not fetching in time?