Anytime an airplane disappears the probability to find anybody alive is small. The day it happened I was already feeling sad about it. I just can't imagine how the families must feel every time news are announced.
Other things on the plane also have similar beacons (the flight recorder, most notably) but have yet to be found, so it's not completely out of the question that they be deployed but not located.
How about a widely held view so far: Possibly held captive by hijackers or terrorists? Not desirable, but better than certain death indicated by debris (if confirmed).
