US investigators suspect that Malaysia Airlines Flight 370 stayed in the air for about four hours past the time it reached its last confirmed location, the Wall Street Journal reported, citing two people familiar with the details.
The report comes as authorities remain uncertain about which ocean to search for the jetliner that went missing on Saturday after taking off from Kuala Lumpur.
It raises the possibility that the plane, and the 239 people on board, could have flown on for hundreds of additional miles under conditions that remain murky, the newspaper claimed.
A mother has described her frustration as she waits for answers on the fate of her missing son who is on board the missing Malaysia plane.
Malaysia's military believes a jetliner missing for almost four days turned and flew hundreds of kilometres to the west.
The wife of a passenger travelling on the missing Malaysia Airlines flight has spoken of her struggle to cope as she waits for news.