Nice article from Vanity Fair on Does Airport Security Really Make Us Safer?.

Bruce Schneier's exasperation is informed by his job-related need to spend a lot of time in Airportland. He has 10 million frequent-flier miles and takes about 170 flights a year; his average speed, he has calculated, is 32 miles and hour. "The only useful airport security measures since 9/11," he says, "were locking and reinforcing the cockpit doors, so terrorists can't break in, positive baggage matching"--ensuring that people can't put luggage on planes, and then not board them --"and teaching the passengers to fight back. The rest is security theater."