"We will be getting our aircraft back up in the air as soon as we possibly can," CEO Alan Joyce said in a statement. Regulatory approval was required, and the airline said the flight schedule would be limited.
The arbitration court heard more than 14 hours of testimony from the airline, the Australian government and unions after the government called the emergency hearing. Workers have held rolling strikes and refused overtime work for weeks out of worry that some of Qantas' 35,000 jobs would be moved overseas in a restructuring plan.
The unions wanted a temporary suspension of the employee lockout, but the airline said the strikes had been too devastating and it needed certainty to continue operating.
Tribunal President Geoffrey Giudice said the panel decided a temporary suspension would still risk Qantas' grounding its fleet in the future and would not protect the tourism and aviation industry from damage.
Qantas is the largest of Australia's four national domestic airlines, and the grounding affected 108 planes in 22 countries.
About 70,000 passengers fly Qantas daily, and would-be fliers this weekend were stuck at home, hotels, airports or even had to suddenly deplane when Qantas suspended operations. More than 60 flights were in the air at the time but flew to their destinations, and Qantas was paying for passengers to book other flights.
Qantas CEO Alan Joyce said before the panel ruled that the airline could be flying again within hours of a decision. He had estimated the grounding would cost the carrier $20 million a day.
German tourist Michael Messmann was trying to find a way home from Singapore on Sunday. He and his wife spent five weeks traveling around Australia but found their connecting flight home to Frankfurt suddenly canceled.
"I don't know the details of the dispute, but it seems like a severe reaction by the airline to shut down all their flights. That seems a bit extreme," said Messmann, 68. "After five weeks of traveling, we just want to go home."
Australian business traveler Graeme Yeatman sided with the airline, even though he was also trying to find a new flight home to Sydney on Sunday after his flight was canceled.
"I think the unions have too much power over Qantas. Even though this is an inconvenience for me, I'm glad the airline is drawing a line in the sand," said Yeatman, 41.
The airline infuriated unions in August when it said it would improve its loss-making overseas business by creating an Asia-based airline with its own name and brand. The five-year restructure plan will cost 1,000 jobs.
Qantas said in August it had more than doubled annual profit to AU$250 million but warned that the business environment was too challenging to forecast earnings for the current fiscal year.