I read your thread, and here is my response...
At least the people on the 4th plane did something.
Besides, we don't know how many terrorists were aboard the flight yet. What if half the plane's passengers were terrorists? Not very good odds. Some of those people had wives and children to think about. Would I have done something? I would like to think so. But I'm a 22 year old grad student with nothing to support but two lizards. If I had a wife and a kid or two, I would be thinking differently. However, once I knew what was planned, it wouldn't matter any more. Many people on the plane probably thought that this was a hijacking for money and not a suicide mission.
However, I do agree with you in that if even half the people on that plane mobilized, the terrorists wouldn't have been able to stop them all.
Ryan