It's possible that somebody landed the plane at some remote airport and is hiding it from the world.
Maybe they want to hold the passengers hostage, although nobody has taken responsibility or demanded a ransom.
Maybe there was something of value in the cargo hold — and this was the world's most elaborate robbery.
Maybe terrorists have the plane and plan to load it with jet fuel and explosives and use it as a missile in the future.
Those scenarios all have holes. A very skilled pilot would have to land the plane at a small airport that normally doesn't accommodate 777s.
They might have had to land in the dark, without normal navigation aids to assist. And they would have to dodge several nations' radar systems, though some have suggested that it stealthily flew in another jet's shadow.
Yet it's hard to rule out anything. It took Thailand's government 10 days to acknowledge that it spotted what might have been Flight 370 on its radar.
Governments aren't necessarily open to sharing all their information, especially when it comes to their military radar capabilities.
But why go to all the trouble of stealing a commercial jet? A cargo plane would be easier to steal.
