The Aviation and Transportation Security Act mandates that by December 2002 100 percent of checked baggage at all U.S. airports be screened for explosives before being put on an aircraft. Will it be possible to meet this ambitious schedule? In this companion report to WP-131, RAND assessed the feasibility of using explosive detection system machines for the job or whether less-expensive explosive trace detection machines could shoulder a significant portion of the load. After studying operations at Dulles International Airport and Dallas-Fort Worth Airport, the authors concluded that a bottom-up approach an airport-by-airport basis was preferable to the top-down approach originally mandated by the FAA. They identified six problem areas and propose a number of improvements that, while not meeting the 2002 deadline, will go a long way toward increasing airport security. This companion report also contains detailed analysis of requirements for baggage scanning equipment, a simulated modeling of airport security operations, and a brief synopsis of the Trusted Traveler Program.