Pursuant to a congressional request, GAO provided information on issues regarding site selection for a new Chicago-area airport, focusing on: (1) how the five candidate sites compared; (2) how a policy committee used a study in selecting a site for the new airport; and (3) how each of the five sites would affect the federal Airport Improvement Program (AIP).

GAO found that: (1) the study did not indicate a clear-cut choice for the location of a new Chicago-area airport; (2) rural sites would cause the least airspace congestion and the fewest air traffic delays, and would cost less than the urban sites; (3) the study did not include cost data for comparing collateral development costs; (4) the urban sites would result in the cleanup of most hazardous waste, but would substantially increase costs; (5) the policy committee used the study as one of several data sources for site selection; (6) the site selection process was strongly influenced by the predominance of policy committee members from Illinois; (7) the study assumed that the Federal Aviation Administration (FAA) would fund 20 percent of the eligible cost regardless of which site was selected; and (8) AIP funding for any of the sites, especially the more expensive urban sites, would affect AIP funding for other projects.