The action, which began at midnight and is scheduled to continue until midday Saturday, concerns the SAS Tech, Avia Express Sweden and Svenska Direktflyg companies.

Swedavia, the national air traffic control, warned of flight cancellations and delays.

Because of the strike, Scandinavian airline SAS has no technicians available to carryout maintenance on their airplanes, resulting in the cancelation of two domestic and two international departures.

“We’ve canceled four flights so far, but as of now things are moving pretty well. We’re doing everything we can to ensure our customers can get where they want to go. If a flight is cancelled we rebook them on a later flight,” SAS spokesperson Elisabeth Manzi told the TT news agency.

The SFF union said the strike was protesting against a stalemate in wage negotiations. The current action is set to cease on Saturday, but could start again next Thursday if no progress is made.

SAS expects to have to ground more flights by the weekend, but still encourages travelers to travel to the airport as they normally would, unless they receive a text message from the airline alerting them that they’ve been rebooked on another flight.