al-Queda is not known for their intelligence. If they were smart, they could have crashed one plane into the Peace Bridge (take out 95% of telecommunications between the United States and Canada) and the three telecommunication hubs in the United States where all international traffic go through (two in New York, one in Seattle). It would have killed just about all international telecommunications and would have done far, far more damage than what they did. They went for the visuals. I don't think if anyone wants to nuke the U.S. they would think of starting in Missouri.