Our friends at Families of September 11th have noted that:

Images often evoke the thoughts, feelings and sensations of an experience from the past--live events can be even more provocative. We were disturbed to learn about yesterday’s avoidable incident in which the 747 back-up plane to Air Force One flew so low over Manhattan that, according to a witness, it caused buildings to vibrate and windows to rattle. Many people in lower Manhattan evacuated their offices. “It brought back all the memories of 9/11,” a witnesss was quoted saying to the press. This event is especially troubling because several federal, city, and state agencies had prior knowledge that this event would take place but failed to alert the community.