Since 11th September 2001 there has been a raft of measures brought in to make airports and commercial airlines a more difficult target to reach. We have witnessed an increase in both the range of technologies and personnel deployed to ensure passenger safety. Although primarily designed to thwart terrorism, one of the secondary outcomes of these increased security measures has been the reduction of property-related offenses, particularly larceny and motor vehicle theft, at U. S. airports. Brian R. Johnson and Brian F. Kingshott examine the Changes in the number of reported property crimes at Chicago O'Hare, pre- and post-9/11.