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?
With the way the internet is used on a daily basis to broadcast everyones opinion, not one reference has appears in any news broadcast regarding "we did it"!