In a few cases pilots have been rendered unconcious or killed and their planes have flown on as 'ghost' planes.
So imagining a situation where the pilots of an airliner suddenly die and the passengers are unable to break their way into the cockpit, but this plane is on a direct collision course for a major place like Times Square or the Whitehouse.
Is it possible for the military to legally shoot down a plane over a rural area before it reaches a location where it will kill possibly hundreds?