Germany's biggest airline Lufthansa said it cancelled 140 flights taking off or landing in Munich on Wednesday owing to an eight-hour walkout by its pilots over changes to early retirement rules.
The number accounts for around half of the airline's daily flights in and out of Munich -- Lufthansa's second-largest hub after Frankfurt -- and is affecting some 15,300 passengers, Lufthansa said. 
The cancellations mainly affected the group's domestic and European services. And while intercontinental flights were not hit, delays were expected, a spokesman told AFP. 
The pilots are stopping work between 10 am and 6 pm (0800 to 1600 GMT). 
Lufthansa said it was trying to minimise the disruption and inconvenience caused to passengers.
The airline has been hit by several rounds of industrial action over its plans to change its early retirement policy.
A strike last Friday forced the cancellation of 218 flights and affected 26,000 passengers.