Found this link in an article about a tourist (of course, not from the USA) who was flying a drone and photographing near Windsor Castle. Poor bloke didn't know the Queen was in residence at the time, not that it mattered!
http://www.engadget.com/2015/01/27/drone-guide-uk/
http://www.engadget.com/2015/01/27/drone-guide-uk/
