Hi all, this is my first post on this forum, so sorry if its in the wrong place!! I am trying to design some scenery for an airport. But when I try to add my custom runway I just get glitchy textures (see photo). In Airport Design Editor I have tried to add a flatten vector, but this did not work... Does anyone have any ideas on what I can do to fix this??? Thanks in advance!

Can you raise the height of your runway a tiny bit? It looks like FSX can't decide which one to show because they are at the exact same height. Try moving it up 1/4" or so. You might want to try putting an exclusion polygon the same shape as your runway under it. I've only tinkered with airport design, so that's about as far as I can go. 

Thanks, will give it a go!