Also, the answer might well be "what" instead of who. Many people have pointed out that the cargo manifest hasn't been published, and that the airline declared 50 less seats as available for boarding than the plane had. This means it had several tons of cargo on board.
http://www.thestar.com.my/News/Nation/2014/03/17/missing-mh3...
the blocking off of passenger seats often indicates an especially heavy or oddly weighted cargo.
something else that is notable is that you know several large world governments have continuous satellite tracking of this flight but are not sharing any information about it.
They do?
If you were part of the plan to hide this plan, surely you'd go along with the ruse and send some search teams to go look at some empty water somewhere else.
I'd guess the crews on the ships and planes would have to do so many hours of training a year anyway, so them circling about for a while would probably count towards that.
Combining this fact with the 20 Freescale engineers that were on board is it possible they were transporting some kind of important prototype chips?
Gold, for it's weight, is very expensive. Transporting gold of high enough volumes for it to be worth killing so many people, steal a plane as well as making all of that possible wouldn't be worth it, I would say.
2 tons of gold are something that a reasonable person can actually expect to be able to convert into money without undue risk to his person. A stolen airplane isn't.
People keep talking about how this needs so much sophistication that it's probably a state action.
All I can see is something that one person with good planning could have done. That is, the pilot or the co-pilot waits until the other guy visits bathroom, climbs high enough and disables pressurization to knock out/kill the passengers and the rest of the crew, then disable communications, turn off transponder, sneak out of controlled airspace behind another plane, land anywhere with an unused strip with a truck waiting, abscond with the cargo.
That requires sophistication and careful planning, but is not beyond the realm of the possible.
Given that 2 tons of stolen gold can't be legally sold, I'd suspect that anyone with that kind of cash on hand might be the kind it would be risky to do business with...
If you stole a ton of gold, you could sell it piecemeal for the rest of your life and live like a king.