The search for a missing Malaysia Airlines plane resumed at first light but - as yet - an international task force has found no trace of the aircraft.
Search planes joined a freighter to scan rough seas in one of the remotest places on Earth after satellite images detected possible pieces from the missing plane.
In what officials called the "best lead" of the nearly two-week-old aviation mystery, a satellite detected two large objects floating in the southern Indian Ocean.
They were about 1,000 miles off the south-western coast of Australia and halfway to the desolate islands of the Antarctic. The area is so remote is takes aircraft longer to fly there - four hours - than it does for the search.
The development raised new hope of finding the vanished jet and sent another emotional jolt to the families of the 239 people aboard.
Australian authorities said in a statement that the search had turned up nothing so far. Efforts were resuming with the first of five aircraft - a Royal Australian Air Force P3 Orion - leaving the base in Western Australia for the search around dawn.
A civilian Gulfstream jet and a second Orion were expected to depart later this morning and a third Orion was due to fly out in the early afternoon to scour more than 13,000 square miles of ocean.
A US Navy P-8 Poseidon aircraft was scheduled to leave the base at about 4pm local time (06.00 GMT), but like the other planes, it will have enough fuel for only a few hours before returning to Perth.
"It is a very long journey to the site and unfortunately, aircraft can only have one or two hours over the search area before they need to return to the mainland for fuel," Warren Truss, who is Australia's acting prime minister while Tony Abbott is overseas, told Australian Broadcasting Corporation.
He said that weather conditions in the area were poor and may get worse.
"And so clearly this is a very, very difficult and challenging search. Weather conditions are not particularly good and risk that they may deteriorate."
One of the objects on the satellite image was 24 metres (almost 80 feet) long and the other was five metres (15 feet). There could be other objects in the area, a four-hour flight from Australia, said John Young, manager of the Australian Maritime Safety Authority's emergency response division.
"This is a lead, it's probably the best lead we have right now," Mr Young said.
He warned that the objects could be seaborne debris along a shipping route where containers can fall off cargo vessels, although the larger object is longer than a container.
Mr Truss said officials were working to get more satellite images and stronger resolution to help searchers get a better sense of where the objects are and how far they've shifted since the initial images were captured.
"They will have moved because of tides and wind and the like, so the search area is quite broad," he said, adding that marker buoys were dropped to help get a better understanding of what drift is likely to have occurred.
The Norwegian cargo vessel Hoegh St. Petersburg, with a Filipino crew of 20, arrived in the area and used searchlights after dark to look for debris. It will continue the search today, said Ingar Skiaker of Hoegh Autoliners.
The Norwegian ship, which transports cars, was on its way from South Africa to Australia, he said.