That scenario would make finding the plane a vastly more difficult task and raises the possibility that searchers are currently looking in the wrong place for the aircraft and its 229 passengers and crew.
In the latest in a series of false leads, planes were sent to search an area where Chinese satellite reportedly showed three floating objects off the southern tip of Vietnam.
However, acting Malaysian transport minister Hishammuddin Hussein confirmed yesterday: "There is nothing. We went there, there is nothing."
Compounding the frustration, he later said the Chinese Embassy had notified the government that the images were released by mistake and did not show any debris from Malaysia Airlines Flight MH370.
The plane was flying from Kuala Lumpur to Beijing early on Saturday when it lost contact with ground controllers and civilian radar.
An international search effort is sweeping the South China Sea and also the Strait of Malacca because of unconfirmed military radar sightings that might indicate the plane changed course and headed west after its last contact.
The Wall Street Journal newspaper quoted US investigators as saying they suspected the plane remained in the air for about four hours after its last confirmed contact, citing data from the plane's engines that are automatically transmitted to the ground as part of a routine maintenance programme.
Mr Hishammuddin said the government had contacted Boeing and Rolls-Royce, the engine manufacturer, and both said the last data was received at 1.07am - 23 minutes before the plane lost contact.
But asked if it were possible the plane kept flying for several hours, Mr Hishammuddin said: "Of course, we can't rule anything out. This is why we have extended the search."
He said the search had been widened into the Andaman Sea and Malaysia is asking for radar data from neighbouring countries. India plans to deploy air and sea assets in the southern section of the sea to join the search.
The jet had enough fuel to reach deep into the Indian Ocean.
Dozens of ships and aircraft from 12 nations have been searching the Gulf of Thailand and the strait, but no confirmed trace has been found. The search area has grown to 35,800sq miles - which is about the size of Portugal.
Experts say if the plane crashed into the ocean then some debris should be floating on the surface, even if most of the jet is submerged. Past experience shows finding the wreckage can take weeks or even longer, especially if the location of the plane is in doubt.
More than two-thirds of those on board the plane were from China, and Beijing has voiced impatience with the absence of any results.
Chinese premier Li Keqiang said yesterday he would like to see better co-ordination among the countries involved in the search.
He said the passengers' "families and friends are burning with anxiety, the Chinese government and Chinese people are all deeply concerned about their safety".
He said China had deployed eight ships and was using 10 satellites in the search.