The one thing that strikes me odd about all the talk of hijack (either to destroy the plane in flight or take it intact) is that no-one has claimed responsibility. If you were a terrorist mastermind and wanted to gain from having pulled off this undertaking, would you not be phoning the local media and making it known by now?
If it was a terrorist suicide mission, then I agree. Associates of the guilty parties would have made a statement by now. A suicide of an individual might not be revealed until the personnal effects of the crew and passengers have been searched.
If it was an attempt to take the PAX alive for ransom, it might be some time before they can be moved to secured locations. And if it was intended to take the aircraft, the perps will want to keep things quiet until they use it for some unknown Phase 2 of their plan.