The affected Finnair customers will be contacted directly by Finnair and will then be offered new flight routes or the opportunity to cancel trips and request the money back.
Finnair has, prior to the announcement, allowed customers to rebook trips on July 4 without an additional fee and thousands of travelers have chosen to do this, according to the airline.
Also in June, Finnair canceled a large number of flights as a result of the conflict with IAU.
IAU has also flagged five strike days later in July, but how they would affect travelers is still being evaluated by Finnair. But customers who have booked trips on July 7, one of the strike days, have been asked to rebook the trip.