No debris has ever been found on the surface of the ocean. No debris has washed up on any shore. The pinging that investigators once believed was from black boxes has now been classified as something else. Over a month has passed since the disappearance of MH 370, and investigators are no closer now to finding it, then they were the day after it crashed. Some sources within the investigation now believe the plane may have landed. That would kind of jibe with what some witnesses reported seeing and that whole passenger cell phone ringing thing that occurred after the plane supposedly crashed.
How about this for a thought? People in a position in the Malaysian government to screw with the investigation and the radar were bought off or helped for personal reasons. The pilot was involved. That is all you really need. It is hard to steal a plane and get away with it, but it is not as hard to make a plane turn and avoid bought off radar coverage on a flight on a weekend during the middle of the night.
You then throw enough false leads out or misinformation to keep everyone focused on other things for a few days until it is too late to do anything. Remember how no one knew where to search the first few days. No other governments were willing to help and the big countries of the world were all caught up with Russia and Ukraine.
If a plane crashed or ditched in the sea, even if it stayed intact, which seems impossible, wouldn't something float to the surface or to shore?