These guys must have trained to fly the airplanes themselves. It is simply out of the question that the US crews were in control of those aircraft. With a gun to your head and the certain knowledge of your death and everyone on your aircraft, you hit the water.
The fourth plane is really wierd. I thought at first that there was every indication that it was shot down but if that were the case you'd expect it to have broken up in the air, which doesn't seem to have happened. Did the crew pull the fire handles?
As much as you have to feel for everyone personally involved or related to the victims, the whole world is a nastier place now. If terrorists want to declare war on the US and it's allies, and unrestricted war at that, then give them war.
The governments of those countries known to support and harbour terrorists should be destroyed systematically and with surgical precision. Then an ultimatum should be levied on whoever steps up to fill the vacuum: Give up your terrorists or face carpet bombing.