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.”