PreCheck, a voluntary passenger-prescreening program developed by the Transportation Security Administration, began its pilot program Tuesday at four U.S. airports. Designed to expedite the security process by assessing participating passenger data in advance, PreCheck went into effect at Hartsfield-Jackson Atlanta International, Detroit Metropolitan Wayne County, Dallas/Fort Worth International and Miami International airports. Eligible volunteers include some frequent flyers on American Airlines and Delta Air Lines, in addition to members of the Customs and Border Protection's Trusted Traveler programs, including Global Entry, SENTRI and NEXUS. Participants must be U.S. citizens flying domestically on either American or Delta. Through the program, the TSA will make intelligence-based risk assessments on participating passengers; if successful, the program will be expanded to include additional airlines and other airports that participate in the Global Entry program.