An American anti-war and Palestinian rights activist was prevented from flying home to the United States from Costa Rica because the US government placed him on the No-Fly List, a subset of the FBI’s Terrorist Screening Center Watchlist. FBI and State Department officials interrogated him for 6 hours at the US embassy, questioning him about his First Amendment-protected speech and activities, such as his religious background and practice, his political activism, and his travel to Muslim countries. Based on these questions, and previous FBI interviews, he believes that he was placed on the No Fly List to pressure him into becoming an FBI informant.
http://www.huffingtonpost.com/shirin-sadeghi/kevin-iraniha-no-fly-list_b_1579208.html