heres my question

[snazzlefrag]

My guess is the presence of the fighter jets gives the people on the ground some control of the situation. If there is a terrorist on board and he forces the plane to head somewhere other than the planned landing point, then the people on the ground can give the order to shoot the passenger jet down. Of course, this would be the decision of last resort. The passengers would be considered unavoidable casualties in the attempt to avoid greater casualties.

I agree,

If, as happened on 9/11, the plane is heading to a destination that could potentially kill thousands of people, the last resort would be to shoot the plane down before it reached its target.

Other possible reasons could be to reassure the passengers that the authorities ARE aware of the situation, or to intimidate the terrorists into giving up. Neither of these reasons would likely be the primary reason though...and I think the sight of an F-16 would neither comfort the passengers, nor deter the terrorists.

It would be an AWFUL decision to have to make...to shoot down a plane full of people. This is a prime example of Utilitarian Ethics: Do that action which will benefit the greater good.

Of course, your definition of "greater good" will be different depending on whether you are sitting on the plane that is about to be shot down by an F-16, or sitting in the 80-storey building that the plane is about to crash into.

I'm sure it would not be a decision that is made lightly though. As SimonTam says, it would absolutely need to be the decision of last resort.

Like I said, what an AWFUL decision to have to make.