The number of people on the U.S. government's no-fly list has doubled over the past year, the AP reports. It went from about 10,000 to 21,000 as the government loosened the requirements for being put on it.
The secret list is for those the government suspects of being a terrorist. A person on that list is banned from flying within the United States or to the United States.
"The surge comes as the government says it's close to defeating al-Qaida, after killing many of its senior members. But senior officials said the threat does not stop there.
"'As long as we sustain the pressure on it, we judge that core al-Qaida will be of largely symbolic importance to the global jihadist movement,' Director of National Intelligence James Clapper told Congress on Thursday. 'But regional affiliates and, to a lesser extent, small cells and individuals will drive the global jihad agenda.'
"Those are the people added to the no-fly list, current and former counterterrorism officials said. Most are from other countries; about 500 are Americans.
CNN reports that the jump in numbers also has to do with changes made after the "underwear bomber" incident, in which a Nigerian man hid explosives in his underwear and was able to get on a flight to Detroit on Christmas Day in 2009.
"The United States can now ban people from flying who are 'deemed to be a threat to national security' or who had gone to terrorist training camps, said the official. The earlier standard was to block only those considered a specific threat to try to bring down a plane," CNN reports.