I'd look into that a little more as typically instructors in the US earn $10-15 per hour for flying lessons, and $0 to $10 for ground school. Ofcourse depending on the number of students you have that could work out fine but in most cases you end up with just about enough money to live if at all. Also bear in mind, you will have to convert your IR to JAA back in Europe (assuming your ultimate goal is JAA fATPL)