As many as 150 flights have been grounded at Spanish flag-carrier Iberia as pilots begin protests against the launch of low-cost carrier Iberia Express.
Up to 30 days of strikes are planned, with Iberia taking the matter to the Spanish High Court in an attempt to minimise disruption.
Pilots union SEPLA argues the launch of Iberia Express is a threat to jobs and conditions.
However, International Airlines Group-owned Iberia counters it is vital to increasing profitability.
Flights to Spain, Europe, and Latin America were all cancelled yesterday; with Iberia confining each day of action would cost it approximately €3 million.
A total of 12 days of strikes were held between December and March.
Pilots now plan to strike every Monday and Friday until July.
SEPLA says 8,000 jobs will be lost as Iberia moves a few dozen airplanes to the low-cost subsidiary from its full-service airline.