[Boeing Guy]

We'll the aircraft disappearance is certainly a strange one.
However as others have said, due to a lack of facts there is very little to go on.

So until they find the Flight Data Recorder and Cockpit Voice Recorder (Black but really Orange boxes) there will be little to go on.
As I see it there are 3 possibilities

1, the Aircraft suffered a catastrophic failure in flight resulting in loss of communications.
2, the Aircraft was destroyed in flight in a matter of second, bomb etc
3, the Aircraft Transponder and Acars system was turned off and they flew to a secret airport manned by Elvis and Lord Lucan.

Anything we say will be pure speculation, but let's remember that 239 souls most likely have lost their lives