Talks were underway on Friday evening to find a solution to the strike by Iberia ground staff that will see over a hundred Vueling flights cancelled at Barcelona airport over the weekend.
Union and company representatives first met on Thursday, but the meeting ended without reaching any agreement.
The Spanish authorities set a minimum service during the stoppage of 100% domestic flights to non-peninsular destinations, 54% of international flights and 32% of peninsular flights.
As the Iberia ground staff provide a service for some 27 companies, should the strike go ahead, it could affect around a thousand flights in total.
Iberia says the reasons for the strike are out of its control, while the employees say there is not enough staff to cover the growth in traffic at Barcelona airport.
Barcelona airport continues to grow at a rate of 5%, and last year it exceeded the 50-million passenger mark.
The unions want permanent part-time staff to be made full-time, and over time, to raise staff levels from 400 to a thousand.