I have thought hijacking since Tuesday. it seemed implausible that they couldnt find a plane in a shallow body of water.
I have two possible scenarios, and I am sure US officials are going through these possibilities, and many more.
1. Plane landed, and these people are playing a long game, which sadly means that they would kill, or already killed, all on board. They will hide the plane, sit and wait. Remember, terrorists are often not stupid or rash. There were 8 years before the first bombing of the WTC and 9/11. Other civilizations measure time in centuries.
In a few months or years, they are going to load the plane with explosives or a nuke and head to the closest European city, or if their target is China, the nearest Chinese city. They will try to sneak in under the radar as far as they can, and try to kill as many people as they can.
Scenario 2: They landed, kept the passengers alive, are putting a nuke or explosives on the plane, the passengers back on, and again, headed to a city to do the most damage. The reason I think they may do this is because they perceive civilized people as weak, ie: no air force will shoot down a plane with 239 people on board. I think they are definitely wrong about this. But if they can get really far sneaking in, they may be successful in either scenario.
And I think the pilot is involved, and so do US officials, which has just been confirmed by CNN. Skilled, experienced, I think he flew the plane and will fly it if they are going to use it for bad purposes. What I don't know is if any governments know exactly where it is, and if they are in touch with the hijackers. And I wonder if we will ever know the truth.
Praying for the passengers and their families. It has got to be hell for them.