On September 11, 2001, “The terrorists thwarted the FAA [Federal Aviation Administration] by turning off the transponders and not responding to radio transmissions. As for NORAD’s more sophisticated radar, it ringed the continent, looking outward for threats, not inward. ‘When you looked at NORAD on September 11, we had a ring of radar all around both [Canada and the United States],’ [NORAD’s Director of Public Affairs Major Douglas] Martin says. ‘It was like a donut. There was no coverage in the middle. That was not the threat.’ ”
– Popular Mechanics editors, Debunking 9/11 Myths, Page 20