"The final layer, security on board commercial aircraft, was not designed to counter suicide hijackings. The FAA-approved "Common Strategy" had been elaborated over decades of experience with scores of hijackings, beginning in the 1960s. It taught flight crews that the best way to deal with hijackers was to accommodate their demands, get the plane to land safely, and then let law enforcement or the military handle the situation. According to the FAA, the record had shown that the longer a hijacking persisted, the more likely it was to end peacefully. The strategy operated on the fundamental assumption that hijackers issued negotiable demands (most often for asylum or the release of prisoners) and that, as one FAA official put it, "suicide wasn't in the game plan" of hijackers. FAA training materials provided no guidance for flight crews should violence occur.

This prevailing Common Strategy of cooperation and nonconfrontation meant that even a hardened cockpit door would have made little difference in a hijacking. As the chairman of the Security Committee of the Air Line Pilots Association observed when proposals were made in early 2001 to install reinforced cockpit doors in commercial aircraft, "Even if you make a vault out of the door, if they have a noose around my flight attendants neck, I'm going to open the door." . . .