Turkey has some pretty weird drone laws concerning foreign nationals. Last time I looked, a visitor has to get the drone registered before travel and the registration has to be in the name of a Turkish national (or the application has to be made BY a Turkish national). The application forms are only in Turkish. Oh, and if you do manage to get a Turkish drone registration ... Don't fly a drone anywhere near the Blue Mosque. Greece and Hungary are part of the EU, so EU registration there.