Investigators now look closer to solving the riddle of where missing Malaysian Airlines flight MH370 met its end. But they still have little idea why, so the search for the wreckage, and the all-important black box data recorder, goes on.
So far, cost seems to have been no object. When Hishammuddin Hussein was asked recently how much money was being spent on the search, the Malaysian defence minister stressed it had not been an issue in discussions with other countries.
"Nobody, not the Malaysian government, none of our partners, have talked about dollars and cents," he said on Saturday. "It's all about trying to find the aircraft. It did not even cross our minds."
But the longer the search continues, the more countries may have to consider their commitment to what could be a long haul – it took two years to find the black box in the case of Air France flight 447, which crashed into the Atlantic in 2009.
Since MH370 vanished on March 8, Malaysia has received help from more than two dozen countries, including Australia, Japan, China, the UK, New Zealand and the US.
The Pentagon has set aside $4 million, but that is expected to run out in early April. The US has not said how much more it would provide, but Rear Admiral John Kirby, Pentagon spokesman, last week said it would "stay with this as long as the Malaysians need our help".
China faces more pressure than most countries to stay the course because 153 of its nationals were on the flight, making the issue one of "political face", says Rory Medcalf, an Asia security expert at the Lowy Institute.
(Read more: Hope of breakthrough in missing jet search)
Beijing has sent 11 ships to what is known as the "southern corridor" – a search area that stretches from Malaysia to the southern Indian Ocean roughly 2,500km southwest of Perth. Two Chinese Ilyushin IL-76 transport aircraft arrived in Perth at the weekend, joining the international reconnaissance operations on Monday.
Premier Li Keqiang has said China will continue "as long as there is a glimmer of hope". But although the search has become the country's largest military operation beyond exercises, analysts say there are limits to what it would be able to do alone.
Gary Li, a Chinese military expert at IHS Maritime, said there were questions about sustainability if others cut their commitment, particularly since aircraft are more important for the search than ships.
"They have to rely on the goodwill of others," said Mr Li. "If China goes completely alone, they have very, very few options other than using ships and satellites – a very scaled down version of what we have now."
China has sent one Y-8 surveillance aircraft to Malaysia to fly search missions, but the aircraft does not have the range to reach the search area. While China could deploy the aircraft to Perth and fly missions from there, Mr Li said that would have security ramifications.
"Any specialised Y-8 aircraft would run the risk of being analysed by other countries if it operated abroad, for very little in terms of search and rescue gain," he said.
Japan has committed 113 personnel and five aircraft – even more than the US – to the search, said Masaru Sato, a Japanese foreign ministry spokesman. But he declined to say how much had been budgeted for the operation.
(Read more: Investigators conclude flight MH370 was hijacked)
"The outlook for the search operations is yet to be decided. Japan will continue to extend as much assistance as possible," he said.
Mr Medcalf said that with the search focused on the southern Indian Ocean, where satellites have detected possible debris, Australia, which has played a key role, would be unlikely to walk away.
"Assuming that the search continues in the southern zone, the last countries to pull out will be Australia and China," he said. Australia was involved "for the long haul", said Mr Medcalf, partly because it had responsibility for search and rescue operations in the area, and also because Tony Abbott, the prime minister, last week revealed Australia had received "credible" leads from satellite images.
A spokesman for Warren Truss, Australia's transport minister, said there were no plans to end the search soon and that Australia would "take it one day at a time".
"We haven't considered the costs," he said. "We have an obligation to the passengers and crew and their families."