I changed my mind. From 2 stars to 1. Developers of the game don't know that Earth is round. Ahahaha!!! You can't build the route from Asia to North America through Pacific ocean))) only through Europe))) Lol!! Idea of the game is fantastic. But mathematician model is incorrect. In the middle of Unlock all countries mode you don't earn as much money as you should (according to amount of your routes and airports). So this game is just push you to watch ads even if you paid for game.