Malaysia Airlines (MAS) is looking at the possibility that its lost Boeing 777 tried to return to an airport at Subang, near the capital of Kuala Lumpur.
But officials stressed they were looking at all possibilities as the search for the missing aircraft was widened to focus on the west coast of Malaysia.
The flight to Beijing with 239 people on board vanished on Saturday shortly after it left Kuala Lumpur.
MAS said: “The search and rescue teams have expanded the scope beyond the flight path. The focus now is on the west peninsular of Malaysia at the Straits of Malacca.
“The authorities are looking at a possibility of an attempt made by [flight] MH370 to turn back to Subang. All angles are being looked at. We are not ruling out any possibilities.
“Apart from the search in the sea, search on land in between these areas is also conducted.”
The airline added that no distress calls were made from the 777.
Rescue teams from eight countries using nine aircraft and 24 ships are scouring the seas for signs of the aircraft.
The 777 last underwent maintenance 12 days before the flight and “there were no issues on the health of the aircraft,” MAS said.
The carrier took delivery of the aircraft in 2002 and it has since flown almost 53,500 hours.
Malaysian authorities said they were expanding the search area from 50 nautical miles from where the aircraft disappeared – over waters between Malaysia and Vietnam – to 100 nautical miles.