SAS Scandinavian Airlines was forced to cancel 70% of its flights in Norway, Sweden and Denmark on Friday due to a strike by pilots.
The strike at SAS followed a breakdown in talks over pay and is expected to ground flights over the weekend.
SAS said in a statement: “Domestic, European and long-haul flights have been cancelled, and thousands of travellers will be affected.”
A spokesperson said the carrier hoped to resume negotiations, but described the pilots’ demands as having “very negative consequences” for the airline.
However, the head of the pilots’ union in Denmark, Rene Arpe, said: “The strike could have been avoided if SAS had shown a real willingness to meet us halfway.
“Instead, SAS management thinks their employees must accept worse working conditions, unpredictable working hours and insecurity about their jobs.”
Sweden’s aviation industry confederation described the pilots’ wage demands as “extreme”.
Yet the SAS Pilot Group said the dispute was more about working hours, claiming most pilots lack fixed schedules and can end up working consecutive weekends for up to seven weeks.
The pilots’ group claims to represent 95% of SAS pilots in Denmark, Norway and Sweden and warned its members are prepared for a prolonged strike.