So, couatl crashes at airports that are custom that we own. For example, I've been trying at the MaccoSim Manchester Airport and this is where it never worked.
I moved to another airport in the middle of the Atlantic Ocean and it worked with no issues (after starting back up couatl of course). I was confused, I went back to Manchester to see if it was a slight bug, it then didn't work again at Manchester. I then moved to ANOTHER airport I know I don't have any addons for (Edinburgh) and it's working with no issues!
I purchased Manchester directly from the vendor, and not through the marketplace. It seems that it has an issue with ALL addon airports, and not just marketplace airports, so it'll only work at airports that are default with the sim (or included with the Deluxe/Premium Deluxe airports)