Danish flight attendants at Scandinavian airline SAS stopped work on Wednesday at Copenhagen's Kastrup international airport in a contract dispute, forcing the cancellation of dozens of flights.
"We have 82 domestic and international flights cancelled, both departures and arrivals," said a spokesman for the airport.
Cabin Attendants Union (CAU) leader Verner Lundtoft Jensen said the union had not called a strike.
"It's a wild strike," he said after rushing to the airport. "I am here to ask them to go back to work." SAS spokesman Jens Langergaard said the two sides had negotiated through the night and had agreed to meet again this afternoon.
"It is not legal," he said, referring to the strike. "Every minute it lasts, it has more effect on traffic for the rest of the day."
The union represents 1,600 Danish cabin crew and has been locked in a dispute with the airline over a new contract. The old contract expired on March 1.
The main points of contention are equal pay and pensions for all union members, Jensen said. A mediator has not been able to bring the parties to an agreement.