Penn professor Stephen Gale has frightening scenarios of al-Qaeda bringing this nation to its knees. People listen, but he's not sure they're hearing. In 1998, University of Pennsylvania political science professor Stephen Gale went to Washington with a warning. He told Federal Aviation Administration security officials that terrorists might seize airplanes and fly them into some of the nation's most prized landmarks. Two he mentioned: the World Trade Center and the Pentagon. No one listened, he said. An FAA security official told him that scenario fell into the category of threats the government is powerless to stop - like meteorites....