Ground staff at IAG-owned Iberia began their strike across Spain on Friday - although the airline itself has yet to see much impact.
ADVERTISEMENTGround staff at IAG-owned Iberia airlines have begun a four-day strike at Spanish airports.
Although the move has forced the cancellation of hundreds of flights, the airline has so far reported minimum impact on its services.
Early on Friday, Iberia announced that operations were proceeding as normal.
They said that, because the strike had been expected for weeks as discussions between the company and unions continued, "more than 90% of customers have already obtained a solution to the cancellation of their flight."
Ground staff including baggage handlers are striking over contracts signed with new providers at Spanish airports.
Talks between the company and unions collapsed at the last minute.
Spain's two main unions CCOO and UGT minted to strike from 5 January until 8 January - dates which will disrupt travel over the country's traditional Epiphany holiday.
While it isn’t clear exactly how many people are on the picket line, Iberia told the press that Madrid airport would not be affected.
Those most likely to face disruption include important sites including Alicante, Barcelona, Bilbao, Gran Canaria, Ibiza, Malaga, Palma de Mallorca and Tenerife.
Some 700 flights have been cancelled by Air Nostrum, Iberia and Iberia Express as well as by other IAG partner airlines.
Iberia says only 3,800 of its 8,000 ground service staff currently work at airports where services are now being run by new contractors.
Spanish commercial airports are operated by state-controlled Aena.
In September, the company hired new contractors for services which had previously been provided by Iberia in many airports. That angered unions, despite the fact that the new suppliers had promised to retain workers as well as optimal working conditions.
Iberia is going through the Spanish courts, challenging the new contracts. They have called the strike action "irresponsible".