Australia's government has ordered an emergency arbitration hearing after Qantas Airways grounded its global fleet amid a bitter dispute with striking workers, stranding passengers around the world.
Government leaders, who expressed frustration over the airline's actions, were expected to argue at the hearing that Qantas should be forced to fly in Australia's economic interests.
"It's not our place to start allocating responsibility, but what I also know is there is a better way to resolve these matters ... than locking your customers out," assistant treasurer Bill Shorten said before the hearing in Melbourne. "We want more common sense than that."
Qantas, the world's 10th-largest airline, announced on Saturday that it would ground all flights.
But chief executive Alan Joyce said the airline could be flying again within hours if the three arbitration judges ruled to permanently terminate the grounding and the unions' strike action.
The unions want the judges to rule for a suspension so the strikes can be resumed if their negotiations with the national flag carrier fail.
"Within six hours, we can get the fleet flying again" after the aviation regulator provides a routine clearance, Mr Joyce told Australian Broadcasting Corporation television. "We have to wait and see what that process generates," he said.
Planes already in the air when the grounding was announced continued to their destinations and at least one taxiing flight stopped on the runway, a passenger said.
Among the stranded passengers are 17 world leaders attending the Commonwealth summit in the western Australian city of Perth. When the grounding was announced, 36 international and 28 domestic Australian flights were in the air, the airline said.
Qantas, which flies 70,000 passengers a day, said 108 planes were being grounded at 22 airports, but did not say how many flights were involved. Spokesman Tom Woodward said 13,000 passengers were booked to fly international flights to Australia within 24 hours of the grounding.