SPANISH air traffic controllers are to start a series of strikes this week disrupting the travel plans thousands of passengers during the peak holiday season.
They will strike for two hours each morning and two hours each afternoon at airports across the country on June 8, 10, 12 and 14.
Around 80 per cent of foreign visitors to Spain arrive or leave by plane.
Spain’s Ministry of Public Works and Transport said: “Tourists on package holidays can’t change the time or day of their flight as the services they have purchased mostly include hotel stays with fixed and non-changeable dates.
“Therefore the damage suffered by travellers, airlines, hotels and tourist operators will be difficult to repair.”
The unions said it was in response to sanctions handed down by airports operator AENA to air controllers in Barcelona following a strike in 2010.
The union represents around 90% of air traffic controllers and more than 80% of members have backed the strikes.
Five years ago Spanish airports were paralysed due to the wildcat strike which left more than 300,000 passengers stranded.
The controllers were protesting about a new working hours decision approved by the Spanish cabinet.