With Flight 370, the facts that are known are not necessarily substantiated. But any theory advanced must account for all of them. That leaves us with theories that are, to say the least, disturbing, and ever-ready to be revised at a moment’s notice.
The whole thing is very disturbing, actually, but in this case the type of theory I usually reject (conspiracy and/or far-fetched) is probably the one that accounts best for the facts so far.
So for the moment, I go with: a pilot-terrorist, who planned in advance to divert the plane to another location by turning off the signals and flying under the radar, and either succeeded or failed. Along the way, I think it most likely that he killed the passengers through decompression. The goal, and what’s next? To sow terror, and something involving the plane and something hugely explosive. Where? Israel, the US, or China. Why? Because it’s frightening. Who? A person who considers himself a jihadi.
As I said, always up for revision in every one of its aspects. But that’s it for now.