It was the first multiple hijacking in the United States, and the first in the world in more than thirty years. On September 11, 2001, nineteen terrorists boarded four commercial jetliners, all transcontinental flights, carrying a maximum load of 11,400 gallons of jet fuel. Their objective was to take control of the planes once they were airborne and turn them into flying weapons of destruction.
Four targets had been chosen, all iconic American buildings that would send a clear message of the depth of their hatred for the United States. All four planes crashed, killing all on board—terrorists, crew members, and passengers, along with hundreds who were killed inside the structures, on the ground, and the men and women who ran into collapsing buildings in an effort to try and save others.
Only one of the four planes did not find its target. Thanks to cellular phones, passengers heard of the other crashes and chose to sacrifice themselves rather than let another plane devastate a fourth target, killing even more innocent people.
What little is known of actual events on board the four flights comes from brief radio communications, observation by witnesses on the ground and phone calls made by crew and passengers. The scenario on all four flights seems to have been basically the same.