Germany's biggest airline, Lufthansa, scrapped more than 1,300 flights from noon Monday as pilots launched a 36-hour strike, their latest in a bitter labour dispute.
In total some 150,000 passengers will be hit by Germany's 10th pilots strike in 2014, a year in which industrial action by train drivers has compounded travel chaos in Europe's biggest economy.
Pilots union Vereinigung Cockpit launched their action for domestic and European flights at noon (1100 GMT), with the stoppage set to broaden to long-haul and cargo routes from 0200 GMT Tuesday.
Lufthansa's low-cost subsidiary Germanwings was not affected by the industrial action.
Europe's biggest airline, Lufthansa said it had to cancel 1,350 flights, almost half of its 2,800 scheduled services, until the end of the strike at 2300 GMT Tuesday.
The mood was generally calm at German airports as Lufthansa had informed customers in advance with emails, text messages and a list of cancelled flights on its website.
Talks between the airline and the union had broken down again Friday night in a dispute that centres on transitional pension arrangements for about 5,400 pilots.
At present, the pilots are allowed to retire at 55 and receive up to 60 percent of their pay until they reach the statutory retirement age of 65.
Lufthansa pilots had previously staged nine walkouts since April, forcing thousands of flight cancellations and taking a heavy toll on the company's earnings.
Lufthansa says that all strike action it faced this year, including by airport staff, had cost it some 170 million euros (about $210 million).
Pilots say they also worry about the future strategy of Lufthansa, including plans for a new long-haul budget subsidiary, as Lufthansa battles competition mainly from low-cost carriers.
Union spokesman Joerg Handwerg charged in comments on news channel NTV that the airline "says, simply, we will strike no new collective bargaining agreements from now on so that we have the greatest possible degree of freedom".
Lufthansa spokeswoman Barbara Schaedler asked the pilots to "contribute to corporate restructuring", speaking on public radio Bayerischer Rundfunk.
"We are in a very fierce competition and must position ourselves so that we can still safely fly our passengers in 10, 20 and 30 years from now," she said.