Qantas has resumed flights about 48 hours after halting all operations in response to unions' industrial action.
The first flights to take off were from Melbourne to Sydney, and Sydney to Jakarta.
Qantas grounded its aircraft on Saturday night and said it would lock out thousands of employees from Monday, stranding up to 70,000 passengers.
The federal government stepped in and applied to the Fair Work Australia tribunal to either terminate or suspend the action.
The tribunal ordered a stop to all industrial action by both the company and the unions.
In response, the airline began repositioning aircraft early on Monday afternoon and flights began once the all-clear had been given by the Australian Civil Aviation Authority.
Qantas has already been shuttling aircraft between airports so that it was ready to start clearing the backlog of passengers.
Qantas chief executive Alan Joyce says he expects the airline to be at normal capacity by Tuesday.
He says extra staff have been brought in to handle the backlog and four additional international flights were be provided.
Airline operations manager Alan Milne is also confident Qantas will be operating normally within 24 hours.
He says the fleet has been kept in a reasonable state of readiness during the grounding.
However, analysts believe it could be days before the situation gets back to normal.
Australian International Pilots Association spokesperson Captain Richard Woodward says restarting services will be a huge logistical challenge.
Two sides ordered to return to negotiating tribunal
Fair Work Australia says both sides must now return to the negotiating tribunal to resolve their prolonged and bitter industrial dispute.
It accepted that the industrial action that caused the situation would have caused significant national economic harm.
The tribunal of judges took two hours to come to the decision, following 14 hours of hearings over two days.
The tribunal decision has been greeted positively by the government and unions.
Assistant Treasurer Bill Shorten says he is pleased that after 24 hours of turmoil, common sense was restored.
Australian Council of Trade Unions secretary Jeff Lawrence has described the ruling as generally positive.
He says it is unfortunate that it has taken the intervention of the Federal Government to force Qantas to negotiate about issues of job security and end the lockout.
Transport Workers Union secretary Tony Sheldon says the union's fight for job security is not over.
He says the Government must back the unions' demands for a guarantee that Qantas jobs will remain in Australia.
If there is no agreement at the negotiating tribunal within 21 days, the case will go to arbitration.
However both Qantas and the Transport Workers' Union were "hopeful" agreement could be reached.
