I've just been reading a report on the Daily Mail website that says that the White House has deployed a warship, USS Kidd, into the Indian Ocean after 'information' came to light that the aircraft might be there. It's possible that the US has a submarine there that has heard the signal from the aircraft's beacon (the ELT, or Emergency Locator Transmitter)
I've also had a chat with DH, who deals with goverments, about some of the language used that I found a bit odd.
The report says:
Hshammuddin Hussein said reports claiming data sent fromt he engines suggested the plane had kept flying for four hours were "inaccurate"
That's an odd choice of words and I'm not a politician but DH confirmed my suspicion that 'inaccurate' doesn't mean 'wrong'. It means, in political language as well as real English, 'not precise'.
If you read between the lines of the statement, in political language, it means the engine data wasn't supplied for 4 hours. It might have been 3 hours, or 5 hours, or 4 hours and 1 minute. But it wasn't 4 hours.
I can't confirm any of that and I emphasise all I'm doing is speculating but things start to add up to the flight going out into the Indian Ocean, whether accidentally or under duress (hijack).