Hi
I use a program called AI Airport Enhancer. It works for me in the latest Prepar3d. I use AI aircraft taken from World Of AI packages. The WOAI installer can be used to manually open the required package to any folder specified. I add the aircraft to the Sim Objects "aircraft" list and then run the AI Airport Enhancer program - so far no problems. The Prepar3d version can be found on the web - in my setup (Windows 10) it has to be run "as Administrator"
Hope this helps
Warren (aspen31)