A good start would be the FAA website (Google it) - just like you can find useful info on the UK CAA website.
In this business, nothing stays the same forever and thus info that may be correct years ago is not necessarily the same today.
Maybe the "free skies" starting next year will provide some relief, but I doubt it. Each state will want to keep it's own protective world even though it is now a global world in business and aviation.
Good luck.