[Arkinsaw]

Terrorists didn't want to give the passengers the satisfaction of winning.

But if they crashed into field in Pennsylvania rather than into the White House as planned then the passengers did win.

The only way you can say that they did not win is if you think the passengers motivations were simply to save their own skins. Based on the phone conversations I don't believe that this was their primary motivation.

[Poohbah]

I'm looking at it from the terrorists' POV for a second, explaining their motives.

Their goals:

1. Fly into the White House.

2. Kill a bunch of Americans. (Which would be achieved by Condition #1)

In wargaming terms, getting both #1 and #2 is, from the terrorists' POV, a decisive victory. Getting only #2 is, again from the bad guys' POV, a tactical victory. But it's still a victory. They succeeded in killing a bunch of Americans. Whether the Americans accomplished their own goals or not is irrelevant to the terrorists.