The list is used to pre-emptively identify terrorists attempting to buy airline tickets or board aircraft traveling in the United States, and to mitigate perceived threats.
When a person books a plane ticket, certain identifying information is collected by the airline: full name, date of birth, address, etc.
Wail al-Shehri and Satam al-Suqami were selected for extra screening of their checked bags before they boarded American Airlines Flight 11 at Logan International Airport in Boston, Massachusetts.
Some of those requirements were: Like its predecessor, the CAPPS II proposal would rely on the PNR to uniquely identify people attempting to board aircraft.
Law enforcement would be contacted in the event that the person was either present on a terrorist or most-wanted list or had outstanding federal or state arrest warrants for a violent crime.
The CAPPS II system was criticized in a report by the United States General Accounting Office in early 2004, and faced increased opposition from watchdog groups like the American Civil Liberties Union (ACLU), ReclaimDemocracy.org, and the Electronic Privacy Information Center (EPIC).
Shortly thereafter, the TSA announced a successor program, called Secure Flight, that would work in a way similar to CAPPS II.
TSA hoped to test Secure Flight in August 2005 using two airlines, but it was blocked by Congress until the government could prove that the system can pass 10 tests for accuracy and privacy protection as follows: The Intelligence Reform and Terrorism Prevention Act (IRTPA) of 2004 requires the Department of Homeland Security (DHS) to assume from aircraft operators the function of conducting pre-flight comparisons of airline passenger information to federal government watch lists for international and domestic flights.