WNYC
The fact that the latest "ping" from the jet's satellite communication system was picked up 7 hours after the plane's transponder was switched off suggests that the plane could have flown about 2,000 miles from its last known position, a range that could have taken it into central Asia (or, via a southern route, toward islands in the southern Indian Ocean).
It seems highly unlikely that someone would go to the trouble of seizing, hiding, and then flying the jet for 7 hours if the goal was merely to kill everyone on board and commit suicide. Once the person or people involved had control of the plane, if the intention was merely to destroy it, this would have been easy.
Instead, the person or people who took control flew the plane in a specific direction for at least 7 hours. Whether they reached their intended destination or not remains unknown. But it seems increasingly conceivable that they might have - and that the plane might now be in the hands of people who have another mission for it in mind.
What might the plane's destination have been?
WNYC put together the map below of all the runways on which the 777 could have landed that are within the plane's estimated range at its last point of contact.
If the plane was indeed seized with the intention of being flown to a destination, that destination could well be on this map. And it's also possible that the jet could have landed in a desert, or anywhere else with 5,000 feet of straight, flat ground that could be used as a runway. (If the goal was for the plane to take off again, it would need about 9,000 feet).
Jeff Wise at Slate argues persuasively that the plane might have been headed toward - and reached - ">a destination in central Asia. This seems much more logical than the southern route.
But why steal a plane a fly it somewhere? And what of the passengers and crew?
Some have speculated that the next mission for the plane might be an attack of some sort.
We will probably know soon enough.