Bill Still has opined from the beginning that the U.S. knows where the plane is, and that it is trying to negotiate the release of the hostages, while diverting attention away from the actual circumstances. The search may last up to 2 months, say Americans.
Of course, if the plane has been hijacked to Afghanistan or Pakistan, and is still flyable, it represents a major terrorist threat. This plane is a 777ER, where 'ER' stands for Extended Range, meaning it is theoretically capable of flying 5,235 to 9,380 nautical miles. If American authorities do know where the plane is, and are not telling in order to negotiate the release of the hostages first, some very serious backpedaling from the official story will have to take place before they can retrieve the plane. Or, they might just decide to use one of the many drones in the area already, and blow the $320 million plane up, without telling the world anything.
*** UPDATE 4/25/14 ***
This video just released by Bill Still vigorously refutes what he calls the "Southern Route Theory." The data on which this theory is based has been withheld, possibly at the request of the British Government, and the whole idea of a hijacking in order to ditch the plane 7 hours later into the southern ocean doesn't hold up to scrutiny: