Australia's Qantas Airways said it was grounding all aircraft over a labour dispute and the move would cost it A$20m ($21.4m) a day.
Alan Joyce, the airline's chief executive, told a press conference in Sydney on Saturday that all aircraft would remain grounded indefinitely until unions representing pilots and ground staff reached an agreement with Qantas over pay and work conditions.
Joyce said: "We have decided to ground the Qantas international and domestic fleets immediately.''
The carrier, which has been hit by a series of strikes, said all employees involved in the action would be locked out from Monday evening and flights grounded from 0600 GMT Saturday.
"Pilots, licensed engineers and baggage, ground and catering staff are essential to Qantas operations and the lockout will therefore make it necessary for all Qantas aircraft to be grounded," the airline said.
Flights already in the air when the announcement was made will continue to their destinations.
"However, there will be no further Qantas domestic departures or international departures anywhere in the world," Qantas said.
"This step is being taken in response to industrial action taken by these unions."