One year ago, the US no-fly list was at about 10,000 names; today, it has more than doubled to around 21,000. The list has been growing at a quick clip ever since the failed Christmas 2009 "underwear bomber" plot, after which the government lowered the standards required to place people on the list. The new standards would have ensured that would-be bomber Umar Farouk Abdulmutallab was on the list, which would have helped officials to catch him before he attempted to carry out his plot, the AP explains.
The larger watch list comes even as the US touts the number of senior al-Qaeda members it has killed, but the government says that the country is threatened by many others beyond that group. After the 2009 incident, intelligence agencies began scouring old files for names that should have been added to the terror watch list as well as new names to add based on the new standards. Now, a person can be added to the no-fly list—which includes mostly foreigners but around 500 Americans—even if he or she is considered a general threat, rather than a specific aviation threat. (Read more no-fly list stories.)