Pilots at Scandinavian carrier SAS walked off the job in Sweden, Denmark and Norway on Friday, stranding more than 72,000 travellers as 673 flights were cancelled, the airline said.
A total of 1,409 pilots were on strike, affecting domestic, European and long-haul flights, SAS said, predicting that 170,000 passengers would be affected through to Sunday.
The pilots have gone on strike as wage talks break down, triggering queues at airports as the carrier cancelled around 70 per cent of its flights.
The airline hoped to reach an agreement as soon as possible.
"As a consequence of the strike, domestic, European and long-haul flights have been cancelled, and thousands of travellers will be affected," SAS said.
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SAS said it was prepared to continue to negotiate but there would be "very negative consequences" for the company if the pilots' conditions were met.
Unions called for 1,500 SAS pilots to go on strike on Friday if no agreement was reached on wages and other issues after an earlier round of talks failed.
"The strike could have been avoided, if SAS had shown a real willingness to meet us halfway," Rene Arpe, chairman of the Danish pilot union, said.
The aviation industry's employer body in Sweden said pilots held onto their "extreme wage claims", demanding a 13 per cent increase despite what it calls already high average monthly wages of 93,000 Swedish crowns ($US9,759.89).
"We had wished that the pilots had taken a greater responsibility in this situation," Torbjorn Granevarn, head of negotiation at the Swedish Confederation for Transport Enterprises, said.
The strike does not affect flights operated by SAS partners, which make up approximately 30 per cent of all departures, the airline said.
SAS is in the midst of renewing an ageing fleet after spending years cutting costs in the face of competition from budget carriers.
