Why Didn't F-15s Shoot Down the Stolen Sea-Tac Airliner?

I think the policy is to try to get a safe landing as long as he isn't threatening others

I'm guessing that as long as he didn't start flying towards a populated area the pilots didn't want to kill a fellow American.

Shooting down is so far down the priority list that the pilots and controllers probably hadn't even gotten to the page that had that option on it.