Missing 777 Flt 370

So where could it be?  If it crashed at sea, we ought to spot floating wreckage.  If we are looking in the right place. 
   There is evidence that the plane changed course 90 degrees or more to the west.  At 600 mph, it could go a long long way in an unexpected direction.  The 777 is designed for long range trans oceanic flight, and can carry enough fuel to stay up for 10-20 hours.  Which means it could be nearly anywhere on earth. 
  Air traffic control radar mostly works off transponders.  These are descendants of WWII IFF units.  When struck by a radar transmitter pulse from the ground, the transponder replies with  simple code with perhaps 25 watts of power.  That is humungously stronger than the "skin paint" return of the transmitter pulse reflected off the aircraft skin.  It gives a good bright solid pip on the ground radar screen and also gives an ID and the altitude.  Air traffic controllers work with the transponder pips, and may not see or may ignore the much fainter skin paint pips.  Turning off the aircraft's transponder makes it very difficult to see on ATC radar.  Flight 370's transponder pips disappeared off radar.  The 777 has two transponders, it is unlikely that both of them failed at the same time.  Either someone switched them off, or the plane blew apart in midair, or it crashed into the sea, (or both).  Nothing less would silence the transponders. 
   There are reports that a military ground radar saw the missing plane, flying way off its planned course.  If the plane was hijacked, all they had to do is fly at 1000 feet or so and few to no ground radars can see them.  I remember USAF air defense exercises.  A target aircraft would be sent way up north, then turn around, and fly back south into US-Canadian airspace.  The radars were supposed to pick him up and vector fighters onto him. This particular morning, a bright and sunny morning, fine flying weather, the radar operators were calling back to SAGE HQ and complaining that they could not see the target.  SAGE would ask the target to "come up another 1000 feet".  Target was not visible to ground radar until he was a 9000 feet. 
  I'm pretty sure a 777 at 1000 feet would not get picked up on today's ground radar. 
  If it crashed at sea, we ought to find wreakage.  If it crashed in the jungles, we might never find it.  We lost an F-111 Aardvark somewhere in Laos during the war.  We never did find the wreck.  It just knifed thru the triple canopy jungle, the leaves closed up behind it, and it was gone.  Granted that a 777 is bigger than the Aardvark and ought to make a bigger ground footprint, but who knows. 
   Final possibility.  They might have landed the plane in one piece, somewhere.  A good pilot could probably get a 777 down on a very short strip.  Might blow a few tires, but the plane ought to survive.  And now we have to beginnings of a James Bond movie.