Malaysia's Prime Minister has just announced that the investigation indicates onboard communications most likely disabled by the crew and that the change of flight course that followed looks like deliberate action. This aircraft could be really hijacked, but for what purpose? Ransom? Where did it land? Did they even make it to some runway?
The crew totaled 12 people. Even if one or two of them were actually terrorists, the others would have been able to outmaneuver them.
Yes, assuming that the rest of the crew were aware of what was going on and that the plane was heading in wrong direction. Even if they were, was it possible that the captain (or whoever happened to be behind the controls) locked himself in the cockpit? Afaik, those doors are pretty tough.
Anyway. For whatever reason MH370 has stopped all comms and changed its course I find it hard to believe that they (pirates, terrorists, captain gone mad...) could land and then hide such a big plane without anyone (military, civilian air control, locals) ever noticing it.