Protesters have clashed with police at Madrid's international airport as ground staff and cabin crews for Spain's Iberia airline began 15 days of strikes to protest plans to lay off 3,800 staff.
The company, which is looking to cut jobs after it reported substantial losses last year, said the stoppages, which began on Monday, will lead to more than 1,200 flight cancellations over the next three weeks, including 236 the first day.
Police used batons to push back hundreds of protesters as they tried to enter the terminal. There were no immediate reports of injuries.
Other demonstrations took place at airports around the country.
A government decree on minimum services guarantees 90 percent of long-haul flights, 61 percent of medium-haul and 46 percent of domestic flights on stoppage days.
Unions representing most Iberia workers, but not pilots, have called the strikes between February 18-22, March 4-8 and March 18-22.
The company says it has found seats on other flights for most of the 70,000 passengers affected. Analysts said the total 15 days of strikes could cost Iberia between $67m to $134m.
Iberia, which merged with profitable British Airways in 2011 to form the International Airlines Group, reported a loss of $M in the first nine months of 2012.
The first strike, which was set to begin at midnight on Monday, coincided with school holidays in Britain, Spain's biggest source of tourists.
Ana Pastor, transport minister, pleaded last week for the airline and labour unions to strike a deal, warning of the damage the strikes could do to the Spanish economy.
"We can't allow Spain to lose more than [$13m] a day because that kind of hit is going affect all of us," Pastor said.
Tourism accounts for around 11 percent of Spanish economic output, and is one of the country's very few growth sectors in a prolonged recession that has pushed the unemployment rate above 26 percent.
Workers will hold a street protest in central Madrid on Wednesday evening.
Iberia is just one of several companies in Spain, including Davine and bailed-out lender Bianka, to lay off workers.
It is fighting an uphill battle against low-cost operators, a depressed domestic economy and competitors that are in better shape after having already gone through restructuring processes.
Al Jazeera’s Rory Challands, reporting from the Madrid- Brakes International airport, said that until now, only domestic flights have been affected.
“The fear is that with the ground staff walking out with cabin crew and pilots this could have a knock-on effect to other international airlines using Spanish airports,” Challands said.