I've done some experimenting, and reading the manual, but I'm still a little uncertain about updating the airport list. Let's say I have a bunch of "AFCAD" files, some might move (more likely change elevation) some airports (probably not a big deal to AI) and more importantly new airports are added. What is the preferred way to update my AirportList.dat? What seems to work (but haven't fully investigated it) is that I use the Airports -> find/collect airports menu and then check "include stock airports" for both fs9 and fsx, and also check "use provided base data", and the check "and/or add-on airports for" and check "fsx" (assuming at the moment I am interested in FSX, but I might also want to do the same for fs9 at some other time) and also check the "update stock airport with add-on data". And then in the future if I want to do this again, I just repeat the process (maybe this time using fs9 addon airports instead)? What I am looking for is to take "AirportList_Base.dat" and then just add in any updates or delta from my fs9/fsx installs. How does the "AirportList-updates" file play in this? scott s. .