[Always A Marine]

They would have had to jam all comms because one sat phone on board would ruin the plot. I know that some flight crews carry them.

Incapacitating the passengers is a lot easier than many would think. If the cabin is depressurized and oxygen shut off at high altitude, all of the passengers will be unconscious very quickly (while the pilots "breathe normally" from a separate oxygen supply in the sealed cockpit). And they can be quickly dead if that is desired -- and I think that is exactly what happened.

[USAF80]

True, but what would be the point? It’s a passenger plane not a B2. Much easier to use one of their regularly scheduled flights to pull off any sneak attack.

[virgil]

I think that depressurization is the reason for the plane's disappearance. I think I read somewhere it was reported a few years ago that the 777s were developing cracks that could result in a loss of cabin pressure and the planes needed to be inspected for it. I think they all died of hypoxia, pilots included. Like Payne Stewart's Lear Jet, it finally ran out of fuel and fell from the sky. The question is where did it fall?

But the hijacking scenario is still interesting. I would think they would want the plane for ransom and not to use as a weapon, though.

[Cvengr]

If they went to this much trouble to steal the airliner, they’ll also keep the passengers alive as hostages.

Be prepared for the jet to show back up with them onboard, happy to be released, but a question if the jet is now an assymmetric WMD. With the passengers on board, there will be incentive not to shoot it down, but to allow it to fly somewhere with controlled security.