Safe at home? An experiment in domestic airline security

The paper describes a scientific experiment about a contentious policy issue: What costs and disruptions might arise if US domestic airlines adopted positive passenger bag-match (PPBM), an antiterrorist measure aimed at preventing baggage unaccompanied by passengers from traveling in aircraft luggage compartments? The heart of the effort was a two-week live test of domestic bag-match that involved 11 airlines, 8,000 flights, and nearly 750,000 passengers. Working with the Federal Aviation Administration, the authors played a major role in designing, monitoring, and analyzing the live test. However, the live test provided ‘raw materials’ for an assessment of PPBM rather than the assessment itself. As we discuss, there are difficulties in extrapolating from a short experiment involving 4% of domestic flights to the steady-state consequences of systemwide bag-match. Our findings challenge the widely held industry view that PPBM would have grave impacts on domestic operations. We ultimately estimated that, under usual operating conditions, PPBM would delay domestic departures by an average of approximately 1 minute per flight. (Approximately one-seventh of flights would suffer bag-match departure delays, which would average about 7 minutes apiece.) Implementing bag-match would cost the airlines roughly 40 cents per passenger enplanement, and would require virtually no reduction in the number of flights performed. Restricting bag-match to 5% of passengers chosen under a security profile would cut these delays by about 75% and these dollar costs by about 50%.