One possibility is, the terrorist hijacked the plane, force to landed on the ocean as it was done on Hudson Bay therefore there is no debris. Now it sitting on the bottom of the ocean.

There is a small button that pilot/copilot can push easily when a plane is hijacked, that sends distress call and reports that the plane is being hijacked. It's discrete and can be done very easily. Unless the Hijackers took control of cockpit without the pilots being able to push the butttons, it's very hard for that signal not to be initiated. No such signal was initiated so I highly doubt this was the case.

Either pilot error (stalling) or plane just blew up to pieces before the pilots realized, are my guess.

There is a small button that pilot/copilot can push easily when a plane is hijacked, that sends distress call and reports that the plane is being hijacked. It's discrete and can be done very easily. Unless the Hijackers took control of cockpit without the pilots being able to push the butttons, it's very hard for that signal not to be initiated. No such signal was initiated so I highly doubt this was the case.

Either pilot error (stalling) or plane just blew up to pieces before the pilots realized, are my guess.

What if Pilot were involved on this hijack? I have a high doubt. There has to be something some evidence . I am sure it wasn't the first flight for both pilot and co pilot. They know everything about that plane and it shouldn't be that hard not to provide signal or I have a second thought of Alien Invasion. Yeah i know it might sound ridiculously insane but hey who knows?

the likely range of reasons that brought down Malaysia Airlines Flight 370: mechanical failure, pilot actions or terrorism.

I thought it was mechanical failure but I just read that Jet 777 was traced to the skies above a very small island hundreds of miles from the usual Kuala Lumpur to Beijing flight path.

Now I am puzzled and don't know what happened. May be pilot action.

http://www.cnn.com/2014/03/09/opinion/bergen-passenger-jet-mysteries/index.html

Where's rid when you need him to deliver the most?

I think it the MH370 got some serious problem inside plane. Then, the pilot may have wanted to go back. However, it turned out he could not find land. Crashed and went beneath the vast ocean. Just my few cents.

Thanks for reiterating speculations surfacing around by widespread media, Daum.

http://www.huffingtonpost.com/2014/03/12/missing-malaysia-airlines-satellite-images_n_4951966.html?icid=maing-grid7|main5|dl1|sec1_lnk1%26pLid%3D453311

It took 70 years for Titanic to found and to pull it back from the ocean but that is so long ago.....it's kind of hard to believe of disappearing a huge plane,without a blink of a notice and also failure of all the modern technologies that's been used so far to peruse it, without any results for days!!......hope China is not operating a foul play as they are always found scouting on that side of the vast oceans.

Seriously, where did the plane go? 239 people are misssing and a plane, equivalent to a hotel or small chowk is missing. I can see there is vast ocean/ sea with kilometers depth but still with technology and science of today, they should be able to track a mice sinking in a ocean but can not find a pieces or whereabout of the plane. Its should be there somewhere.