Strike-hit Iberia has cancelled 76 of the flights it was scheduled to operate on 19 February, but says 123 services will proceed as normal.
The Oneworld carrier is facing a five-day coordinated stoppage by a number of its trade unions protesting at almost 4,000 job losses and wage cuts as part of a deep restructuring programme.
Iberia says it is still seeking to negotiate with unions on the cost-cutting plan and is waiting for confirmation on when the next meeting will occur.
During the strikes Iberia says it will operate 90% of its long-haul services, 61% of medium-haul and 47% of domestic flights. A total of 415 flights will be cancelled over the five days.
Additionally, Air Nostrum, which operates regional services on Iberia's behalf, has cancelled 80 flights, while low-cost subsidiary Iberia Express has cancelled 20.
The first day of demonstrations turned violent as airline staff clashed with police at Madrid Barajas airport.
Unions representing Iberia staff say that in the restructuring plan, only 15 of the airline's 400 senior executives are affected, while senior management will see wages reduced by only 20% compared with a 40% average pay cut for the rest of the staff.