More than 1,000 Spanish flights are expected to be grounded due to a five-day strike by Iberia workers protesting against job cuts.
The strike coincides with school holidays in the UK, Spain’s biggest source of tourists.
The walk-out was due to start at midnight, the first of three five-day strikes in February and March to protest against management plans to axe 3,807 jobs and cut salaries at the airline.
The IAG-owned Spanish carrier has cancelled 415 flights between Monday and Friday, although a total of around 1,200 flights operated by various airlines will be grounded because of the lack of handling services at Spanish airports.
The airline said 70,000 passengers would be affected by the first industrial action.
Spain’s transport ministry has guaranteed skeleton services to cover the strike. Iberia said 90% of long-haul flights would take off and domestic services would be worst affected, with almost half grounded between Monday and Friday.
The airline said it had found alternative flights for 60,000 passengers whose journeys would be affected by the strike, while others had been offered refunds or flights on different dates.
Airports across Spain will also be disrupted by union-organised demonstrations between 11am and 2pm on the first and last days of the strike. Workers will hold a street protest in central Madrid on Wednesday evening.
Two further strikes are planned for March 4-8 and March 18-22.