Read every reply so far and I'm a slow reader. throwing my speculation as to why in a couple of different perspectives... here we go...
If this indeed has been carried out by the Captain or flight deck as a whole, the entire point could have been to provide worldwide proof of the relative incompetence of the Malaysian govt. I know others have alluded as such as well. The only thing that gets me with this is that if it was the intent and he/they did use their knowledge of radar shortcomings and weaknesses, what would lead him to put it down in the ocean and likely with some or all fatalities? or even down on land somewhere with no/little most on board as casualties? i guess if this is the case it might never be known.... unless there are indeed survivors recovered.
if this has been done with malicious intent and it is indeed hidden on land for a future attack, i am wondering about those 20 employees. i have tried to follow the tracking of them on these threads and from what i have seen they were ruled out as people who could do something with weapons (feel free to correct me, it would help me follow better), but could they have the knowledge to make said 777 an enormous drone? if so this would be my speculative "it could happen" scenario... fair warning, it is grim... Finding a nuclear device would likely have happened already for this silent faction. They dont need it to be large, just with a legitimate punch (its not about the known nuclear devices on earth, its that one we dont know about that scares me). Device placed in 777 and aircraft is filled and topped off with fuel somehow (hey they pulled the rest of it off so far, why not!?) and bodies of deceased placed in aircraft as well. Drone 777 is flown and attempts to get through any major areas airspace. If this is accomplished they dont need to crash it into anything... they just need to get it close to the main sector of a power grid and detonate and the EMP would take care of their intent, in the process eliminating all evidence, or most all of it.
i know to penetrate far enough is not likely, but if it got that far I'd say their chances were greater than most. My thought's since these other plausible scenarios emerged is not a massive missile with the aircraft, but rather a vessel to carry a small yet effective EMP. This would be a fail safe, if you will, that you wouldn't have to be on target, just close enough and airborne, not even needing to crash to the ground. Taking out the power grid and comms of a civilized nation/continental district even would likely cause more terror and mayhem than we would know what to do with at the time.
I personally would like to see the happiest ending possible where the pilot accomplished his task, landed safely in some remote area where it is rather barren, but still close enough and in the open to be found before the planes rations or locations resources could be depleted to cause malnutrition related deaths. But in reality I am just hoping for closure in one way or another for the families of those on board.
Edit to add: I know it's not likely in my speculation, but nothing seems very likely at this point.
[Edited 2014-03-18 04:21:54]
Fast cars and 'Jet A' - such a sweet smell!