Excerpt:
Muslim advocacy groups say an increasing number of Muslim and Arab U.S. citizens and permanent residents who travel abroad are facing new complications in returning to the United States because of heightened security.
An attempted Christmas day bombing on a Detroit-bound airplane caused soul-searching in government agencies after it became clear that the alleged would-be bomber, Umar Farouk Abdulmutallab, was not on a watch list. Since then, the no-fly list has swelled from 3,400 people to about 6,000, with thousands more on the list for travelers who warrant extra screening.
The lists are not made public, and most people don't know they are on one until they arrive at the airport. In one case, an American says he has been barred from returning to the United States without explanation.
Raymond Earl Knaeble IV said that when he presented his U.S. passport at the airport in Bogota, Colombia, for a flight to Miami last month, "They came back and told me, 'You can't fly with any airlines to the USA.' "