Just a guess, but it sounds like there are so many textures loading while a the airport and auto gen, that the texture load rate slows. I don't get this at airports, but if I am flying using detailed scenery like orbx and I switch to an external view, it can take a while for my aircraft textures to load and I fly a white plane for a while. Similarly, when I switch back to cockpit vie, it takes time for the panel textures to load.
