Passenger prescreening is one security measure among many implemented both before and after the terrorist attacks of September 11 designed to strengthen the security of U.S. commercial aviation. Together, these various measures combine to form a multi-layered aviation security approach. Although the prescreening of passengers on international flights traveling to or from the United States predated the September 11, 2001 terrorist attacks, this process was strengthened after the attacks. The current international passenger prescreening process relies on two different sets of passenger data and involves multiple prescreening steps carried out by air carriers and CBP. The two sets of passenger data include: Passenger Name Record (PNR) data, such as name, address, and billing information that passengers provide to air carriers, travel agents, or online travel companies when making a flight reservation. Advance Passenger Information System (APIS) data, such as name, date and location of birth, and country of citizenship, which is derived from passports and other government-issued documents, such as visas, that most passengers must present to air carriers when checking in for international flights. A central prescreening activity involves matching identifying information about passengers—including name and date of birth—against the No Fly and Selectee Lists that are extracted from the TSC’s Terrorist Screening Database (TSDB) to identify potential security threats in a process often called identity matching. The identity matching step is conducted by both air carriers and the U.S. government. Federal requirements state that air carriers must transmit APIS data to CBP no later than 15 minutes before flight departure for international flights originating in the United States and no later than 15 minutes after flight departure for international flights bound for the United States. In addition to these data, CBP occasionally uses commercial data or data from other government databases during this process to help confirm a passenger’s identity. A second prescreening activity, separate from identity matching, involves using risk assessment tools to analyze passenger data to assess the security risk that a passenger might pose. This constitutes an effort to identify high-risk passengers that may not be on the No Fly or Selectee Lists. Specifically, CBP uses an automated system, called the Automated Targeting System-Passenger (ATS-P), that uses available passenger data to apply a set of CBP-generated targeting “rules” that CBP has determined are associated with increased passenger risk. CBP uses both PNR and APIS data to apply the ATS-P rules. This comparison results in a risk assessment for each passenger indicating the passenger’s relative security risk. A third prescreening activity involves the review of passengers’ travel documents for evidence of forgery or fraudulent use. Depending on the passenger, this document review can occur at three separate time frames during the process of flying internationally, as follows: (1) the State Department reviews the travel documents in advance of travel for passengers who are required to obtain a visa in advance of their travel, (2) air carrier personnel review passengers’ travel documents for authenticity upon check-in for flights, and (3) CBP officers review passenger travel documents either upon the passengers’ arrival in the United States or, in some cases, prior to their departure for the United States. Figure 1 provides an overview of the current passenger prescreening activities as set against the basic steps typically taken to fly internationally—including obtaining a flight reservation and ticket, checking in for a flight, departing from one country, and arriving in another. Before a passenger receives a boarding pass, the air carriers conduct an initial identity match, which (along with CBP’s identity matching process) constitutes the first step of the international passenger prescreening process. To complete this prescreening step, air carriers compare PNR data (information that is self-reported by passengers when they make a flight reservation) against the No Fly and Selectee Lists to determine if there are any identity matches. This prescreening step is required to occur prior to flight departure. The No Fly and Selectee Lists are extracted from the TSC’s TSDB, the consolidated federal government terrorist watch list (which contains the names of known or suspected terrorists). Persons on the No Fly List are deemed to be a threat to civil aviation and are therefore to be precluded from boarding an aircraft traveling to, from, or within the United States. Being on the Selectee List does not mean that the person will not be allowed to board an aircraft or enter the United States. Instead, persons on this list receive additional security screening prior to being permitted to board an aircraft—this screening may involve a physical inspection of the person and a hand-search of their luggage. Examples of PNR data that may be collected at the time a reservation is made include a passenger’s name, home address, telephone number, frequent flyer information, and e-mail address. If an air carrier determines that a passenger’s identity matches an identity on the No Fly List, TSA requires the carrier to contact the TSA Office of Intelligence so U.S. authorities can further verify whether the passenger’s identity matches the watch-listed identity. CBP also conducts an identity matching process after air carriers conduct their identity matching, but CBP’s process utilizes APIS data. These data are generally gathered from the passenger’s passport—a document required of almost all passengers flying into and out of the United States. In most instances, these data are recorded electronically from the traveler’s machine-readable passport. This process records information from the passport directly into the air carrier’s computer systems, thereby avoiding potential errors that could occur by key-stroking the data. CBP uses the APIS data to conduct identity matching using its automated systems including its law enforcement databases and the No Fly and Selectee Lists, which CBP transfers to its Treasury Enforcement Communications System (TECS). If this review produces a positive match to the No Fly List, the TSA Office of Intelligence is contacted to confirm the match. While the above prescreening activities focus on determining whether any passengers are on the No Fly and Selectee Lists, CBP also conducts a second prescreening step to identify other passengers, not on the No Fly and Selectee Lists, but who may nonetheless present a potential security risk. This step is a risk targeting process that occurs for international flights traveling to or from the United States. CBP conducts this risk- targeting using a computer-based system called the Automated Targeting System-Passenger. This system compares passenger data (both PNR and APIS data), along with data from government databases (including the TSDB), against a set of targeting rules. According to CBP officials, this risk-targeting process reflects CBP’s experience with indicators of possible illegal or other activities that CBP is responsible for monitoring. This comparison results in a risk assessment for each passenger that CBP uses to determine if the passenger requires additional CBP contact—either before the passenger boards a U.S.-bound aircraft or upon the passenger’s arrival in the United States. If a passenger’s risk assessment indicates an elevated security risk, CBP may decide to take additional security actions to gather more information about the passenger. Additionally, CBP can also decide that a passenger’s risk level is sufficiently elevated that the passenger should be prevented from boarding a flight. If the flight is abroad, CBP officials stated that they can coordinate with State Department Officers to contact U.S. Embassy Legal Attaché officials assigned abroad at foreign embassies and consular offices. These Legal Attaché officers coordinate with foreign law enforcement personnel to identify, interview, or inspect the passenger before allowing the passenger to board the flight. A third prescreening step involves air carriers and CBP determining the authenticity of passenger travel documents. Before issuing boarding passes on flights departing from or arriving in the United States, air carriers are required to review each passenger’s travel documents, including passports and visas, to verify that the passenger is properly documented for the intended destination. For U.S.-bound passengers, air carriers are also required to validate that the passenger’s passport information matches the APIS data that the air carriers electronically submit to CBP. CBP provides periodic training to air carrier personnel to help them determine the authenticity and completeness of passenger travel documents. CBP’s review of passenger documentation can occur in multiple locations. For example, CBP is always required to inspect travel documents for passengers on international flights arriving in the United States. However, in some overseas locations, CBP officials also review passenger documents prior to the passenger boarding a U.S.-bound international flight. The current prescreening process is under revision and under a proposed plan, the U.S. government will take over the process of identity matching passengers against the No Fly and Selectee Lists from the air carriers prior to flight departures. As part of the Intelligence Reform and Terrorism Prevention Act of 2004, Congress mandated that DHS issue a notice of proposed rulemaking (NPRM) by February 16, 2005, that would allow CBP to conduct its comparison of passenger information against the No Fly and Selectee Lists before the departure of all international flights traveling to or from the United States. CBP issued its NPRM on July 14, 2006, and provided for a public comment period. Concurrent to the changes that are being considered for conducting international passenger prescreening, TSA, the agency charged with ensuring the security of all modes of transportation, is in the process of modifying domestic passenger prescreening procedures. TSA is required, by the Intelligence Reform and Terrorism Prevention Act of 2004, to develop a prescreening program through which TSA would assume the domestic watch list matching function currently conducted by air carriers prior to domestic flight departures. TSA has named this prospective prescreening program Secure Flight.