Amazing game, you've got a great base here, the videos explaining everything were amazingly enjoyable just by themselves.
I know you haven't put a lot into the gameplay still so I'll try to give a few ideas there. For me at least, it was rather difficult figuring out where I was, specially in large masses of land or water, or at night. I think a compass could help a lot, knowing where north is could be enough, if not you could even have a mini map, or something more simple, a radar that bias faster as you get close to your destination.
Aside from that you could play around with having to pick up something in a country, and dropping it in another, some turbos, gas, countries in war that try to shoot you down, this could also become a great dogfight game.
Keep up the great work, I will definitely be keeping up with it :)