I have set fast travelling to cost 10 real money. However, it doesn’t seem to get any money from player when they hop on the eagle, and not even when they land.
Tested also with in-game gold, and can confirm that player with 0 gold just hops on the eagle.
Not even the Microtransactions section from Daily reports seems to register it. There are so many eagles on the air, that I should be a millionaire right now.