I think I know now why your try failed. You have just edited the airport.db. But then there is the Runway.db, which is linked to the Airports.db, as well as the Sids.db and Star.db. You just need to find all entrys with LOXG or whatever in any of those files and it should work. I mean it makes sense that the aircraft crashed when having sids, stars rwys but no proper airport for it.

Edit: Even Cthulhus has made it