Where Did Flight 370 Go for 4 Hours?

5 DAYS 21 HOURS – The fate of Malaysia Airlines flight 370 remains a complete mystery.  The Wall Street Journal reports this morning that US investigators suspect the plane was airborne long after it disappeared off radar screens. Four full hours in fact. Data automatically sent to the ground by the Boeing 777's engines suggest it flew for 5 hours, while air control lost contact about an hour into the flight from Kuala Lumpur to Beijing. Those extra hours could put the plane anywhere from the Indian ocean to the Pakistani border or the Arabian sea, writes the WSJ's Andy Pasztor.

U.S. counterterrorism officials are pursuing the possibility that a pilot or someone else on board the plane may have diverted it toward an undisclosed location after intentionally turning off the jetliner's transponders to avoid radar detection, according to one person tracking the probe.

The investigation remains fluid, and it isn't clear whether investigators have evidence indicating possible terrorism or sabotage. So far, U.S. national security officials have said that nothing specifically points toward terrorism, though they haven't ruled it out.

The huge uncertainty about where the plane was headed, and why it apparently continued flying so long without working transponders, has raised theories among investigators that the aircraft may have been commandeered for a reason that appears unclear to U.S. authorities. (Read the full story.)

Ten countries are participating in the search for the plane and its 239 passengers, with 56 ships, 30 aircraft, at least 10 helicopters, and satellites. The families of passengers have now been waiting for news for nearly 6 days.