In what way was the surprise in the attack
on the World trade Center similar to the surprise in
the attack on Pearl Harbor?
Both attacks involved technological surprise:
the use of aircraft in unexpected ways for which a defense
had not been prepared.
In the case of Pearl Harbor, the US had
not realized that torpedoes could be launched from airplanes
into shallow water. Up until then, the torpedoes were
used in deep water, so their motors could start before
they hit the ocean floor. So it was assumed the safest
place for the US battleships would be in the shallow
waters of Pearl Harbor. But Japanese pilots had been
secretly trained to skim their torpedoes in shallow
water, and that surprise left the US fleet vulnerable
to being sunk from afar by carrier-launched planes.
In the case of the world trade center,
the US had not appreciated that suicidists could convert
an airliner into a piloted missile. With a three-quarter
fuel tank, and moving at 400 miles per hour, it would
impart nearly as much energy as a one kiloton battlefield
nuclear weapon. To guide the missile, the suicidist
pilot required little more than a mail-order global
positioning device. Not conceiving that planes could
be converted to missiles, no defenses, such as sealed
cockpit door, had been prepared.