Narrowing the range of possibilities
I am a Scientist in an industry other than aviation & was about to apply William of Okham’s principle (‘Okham’s Razor’) to the detective process but RifRaf3 beat me to it. Judging from some subsequent posts there is clearly some misunderstanding as to how it should be applied.
Basically W of O was a 13th century logician, mathematician and philosopher way ahead of his time. His ‘razor’ principle, which is in widespread use today in arriving at solutions to scientific quandaries, involves 'paring away’ (with the razor) the least significant information to leave a core of significant facts with which to arrive at the most likely explanation. This will not always be the correct answer, but on the balance of probability it will in more cases than not.
So in this case, we have some knowns (definite facts); some potential information that could have basis (‘from Government sources wishing to remain anonymous’) ; some wild speculation and some outright conspiracy theories.
In the significant category, other than the aircraft has disappeared and is now missing, he would have included the time interval between switching off different communications systems and the apparent navigation between waypoints towards the west that were not on the original flight plan, so Okham would have said that someone is apparently still in charge of the plane and flying it, making ditching or crashing in the South China Sea highly improbable & to be eliminated. Other facts that Okham might have kept in there, but down the list are the fact that this happened at night, with an ER variant of the aircraft (so potentially long range); take off from a Muslim country; and access to a wide expanse of the Indian Ocean with only a narrow peninsula to cross and outrun military radar.
Being way ahead of his time, Okham also knows that, (contrary to some earlier posts) oil slicks can easily be detected by satellite (I use this technology) and that the wreckage has not yet been found, despite the technology being available to many countries and that there is therefore a significant possibility that this aircraft is now on the ground. Okham would also have concluded that this was meticulously planned, way ahead of time, pushing suicide down the list of possibilities.
There we must leave Okham and add some conclusions of our own. An obvious motive might be ransom money, but no one has yet asked for any. The significant possibility that this aircraft was taken for a more sinister motive must now surely now be very high on the list. If so, whatever may be being planned is unlikely to be years or even months away, because the likelihood of the location of the aircraft being found/revealed by informers etc will increase rapidly with time. It is unlikely that someone would steal an aircraft (if that is what has happened) and then start thinking of things that they could do with it. Although this is only a possibility, one would hope that governments of susceptible countries are quietly organising the putting in place or checking of instruments of maximum vigilance to quickly & effectively respond to any threat. Skytrax is right – find the plane.