Is it theoretically possible to disable all of the tracking gizmos and fly the plane somewhere else without anyone knowing?
Sounds a bit fantastical, but......
The short answer is 'yes' it is perfectly possible, but the crew would need to be organised, and in total agreement. Afterall, in this day and age, the first whiff of summat amiss and one of the passengers would have tweeted or phoned or texted
(Pure speculation) It is possible that the black boxes might be removed for maintenance purposes and for operational reasons the plane was rushed back into service having been signed off as fit by a manager who didn't know/check/care that all was in order. This would explain both the airlines reticence and also why the plane hasn't been found yet... no one would own up to that size screw up, but once the aircraft is found, forensics come into play and the subsequent investigation with pull at every thread, regardless of where it leads.
The lack of a debris field speaks volumes, as large jets almost never survive landing on open water... remember that hijacked Etheopian 767 a few years back, text book unpowered landing but a wing tip clipped a wave and the plane entered the water in three pieces. The A320 in New york was mostly shere luck helped by the fact that the aircrafts control systems were fully functional, and that the water was sheltered.
Had it exploded in mid air, at that altitude, visibility is knocking on the door of 200 miles, not to mention the time for burning debris to fall. Did anyone in the area report anything? No one's saying... and looking at this, there was an aircraft in the vicinity at the point it vanished...
http://www.mirror.co.uk/news/world-news/missing-malaysia-airlines-flight-mh370-3221009Entwoods observation about having time to make a distress call is equally important... a significant problem would have prompted a radio call, even if it was a simple 'Houston, we have a problem'.
If you listen to both of these links, they are typical radio exchange from the 'Summat's not right through to the end...
NWS (last ten minutes of SR111
No explosions or swearing, just a radio conversation between professionals dealing with a problem)
1.
http://www.youtube.com/watch?v=wt_Wpcj2iIo2.
http://www.youtube.com/watch?v=CAjJWuWhcoQOne of two things happened to MH370, either catastrophic or orchestrated... the current lack of any debris suggests the latter