We got a hold of the Al Qaeda training manual when we arrested Ramzi Yusuf in the Philipines. In it, they spoke of using planes to bring down "the tall buildings of which they are so proud". Because of the spectacular nature of it. So for Condi Rice to tell the 9/11 Commission "We had no idea they'd use planes as missiles" shows her incompetence.
Actually, they did target the Pentagon, conspiracy theories aside.
Probably the main reasons were that they aimed for the WTC is that it represented the capitalistic wealth and the pride of the US, and also because they are bigger and easier targets to be able hit. You do not have to go down to ground level to hit them.
because as much as anything else, the WTC was the symbol of the USA's capitalist might. A significant deal of resentment towards the USA is over its perceived imperialism through capitalism/business which the WTC represents. Rather than the USA's democracy which the white house and statue of liberty would symbolize.
The main objective of most headsets is far more to get the US to stop interfering in the Muslim middle east (economically and politically) than anger at the existence of a western democracy. They just dint want western democracy and values in their own back yard.
Because that was the most arrogant symbol of America. I personally believe this is all about the Zionists/Jews trying to assert their power on Muslims. If you study both sides you will discover both warn to be the boss and have their people running things.
Some people think the following:
They think the WTC Twin Towers were a money pit. Many floors weren't occupied. And the owners of the WTC were losing quite a bit of money keeping the towers open. There was also a problem of asbestos in the towers that would have cost hundreds of millions of dollars to remove. Some think the terrorist attack was a saving grace for the owners of the complex.