I think it is pretty remote that someone would hijack an airliner full of people and not make any demands. If an organization wanted one they could buy a used one cheap or steal one that didn't have a lot of people on it. It went down somewhere and someone probably took it down. My assessment

I think we shoot it down and we are covering it up.

I think it is in the middle of the Indian Ocean. Terrorist like to brag to much and thus far they aren't chirping.