Under legal pressure , the Obama administration will begin telling some suspected terrorists if and why they are on a list of tens of thousands of people banned from flying to , from or within the United States . The new policy allows for an American traveler who has been denied boarding a commercial airliner to petition the U.S. Transportation Security Administration once to find out whether he or she is on the no-fly list and a second time for an unclassified explanation of why he or she is on the list . In some cases , the government will not be able to provide an explanation because of national security concerns . The changes partially lift a veil of secrecy enshrouding a policy that has been a centerpiece of the government 's counterterrorism efforts since the September 2001 terror attacks . Grounded or not grounded ? Under legal pressure , the Obama administration will begin telling some suspected terrorists if and why they are on a list of tens of thousands of people banned from flying to , from or within the U.S . Above the security line at New York John F Kennedy International Airport in October . But the American Civil Liberties Union , which has been challenging the constitutionality of the no-fly list in an ongoing federal lawsuit , said the changes do n't go far enough in giving travelers the legal due process they are entitled to , including seeing the evidence held against them and getting an opportunity to challenge it . The explanations provided to six travelers so far , which were mandated by a federal judge , have been inadequate , the ACLU said . For instance , in a letter to New Jersey resident Amir Meshal , the government 's explanation for his inclusion on the list was based on information the FBI obtained from Meshal when he was detained in Africa in 2007 , ACLU attorney Hina Shamsi said . The ACLU considers Meshal 's detention to be unlawful and said he suffered abuse . 'From the face of the letter , a neutral decision-maker would have no idea whatsoever that any of that occurred , ' said Shamsi . The Justice Department declined to comment on the specific constitutionality challenges because of the ongoing lawsuit . Justice Department spokeswoman Nicole Navas said , 'We are committed to a process that protects Americans from terrorist threats while respecting privacy and safeguarding civil liberties . ' Last fall , there were about 64,000 people on the no-fly list , according to the government . Typically , less than 5 per cent of those on the list are Americans . The list fluctuates in size . Previously , the government 's policy was never to confirm or deny that a person actually is on list , citing national security concerns . In most instances , travelers assume they are on the list because they are instructed to go through additional screening at airports or because they are told they ca n't board their flights . Travelers have been able to appeal their presumed placement on the list since 2007 . Only a small percentage of appeals the government receives each year have been from travelers actually on the list , the government has said . The TSA gets between 15,000 and 20,000 requests a year , and less than 1 per cent of those are actually from people on the no-fly list , said Homeland Security spokeswoman Marsha Catron . In 2014 , a federal judge in Portland , Oregon , required that the government notify 13 plaintiffs challenging the constitutionality of the no-fly list of their status on the list , and seven were told they were not on the list . The government provided explanations to the six plaintiffs it confirmed were on the no-fly list , including Meshal . One of the explanations included just a 'single cryptic sentence about alleged travel to a foreign country , ' according a court document filed earlier this year . The letters to the six plaintiffs on the no-fly list have been redacted on the public court docket to protect the plaintiffs ' reputations , Shamsi said . 'The government had an opportunity to come up with a fair process but failed , so we 're challenging it in court again , ' Shamsi said . The TSA will continue to handle the petitions under the new policy . The changes are not yet in effect , and have so far only been applied to the 13 plaintiffs in the Portland lawsuit , but the Homeland Security Department said it expects them be in place soon . Catron said individual requests should take months to process , not years . 'These enhancements continue to ensure that individuals who are deemed to be a threat to our aviation security are prohibited from boarding a flight within , or bound for , the United States , ' Catron said .
Previously , the U.S. did not disclose whether a stopped traveler was on the list or why . But facing legal pressure from the ACLU , the Obama administration has enacted a new policy to let Americans know if they are on the list . Comment: However , the government has not promised to reveal why in all cases - citing possible national security threats . Last fall there were about 64,000 people on the no-fly list , and Americans made up approximately 5 per cent .