A Boeing 747-200 freighter of the U.S. airline "Atlas Air" lifts off at Dusseldorf International airport. U.S. air cargo traffic would return to normal much faster than would passenger traffic following a new terrorist attack against the U.S. air transport system, but the nation's air transport industry would be greatly impacted economically by such an attack, according to a new study by researchers from the University of Southern California. Credit: AP Photo/Michael Sohn
