SAS pilots in Norway, Sweden and Denmark started a strike on Friday when wage talks failed, prompting the carrier to cancel hundreds of flights, the company and mediators have said.
A blow in the three Scandinavian countries could affect around 170,000 passengers during the weekend, the company said.
Earlier this month, unions called on 1,500 SAS pilots to strike on April 26 if no wage agreement and other issues were reached after an early round of talks failed.
"Both sides were too far away, and there was no reason to believe that a compromise could be reached," the Norwegian National Mediator said in a statement announcing the collapse of the Norwegian negotiations.
A Danish mediator told Reuters talks that he also failed as SAS announced a strike among Swedish pilots.
"As a result of the strike, domestic, European and long flights are canceled … Flights made by SAS Ireland and subcontractors of SAS will not be affected," the airline said.
Report by Terje Solsvik in Oslo and Jacob Gronholt-Pedersen in Copenhagen; edited by Jacqueline Wong and Gopakumar Warrier