Lufthansa pilots will extend their strike to a second day tomorrow.
The industrial action, protesting pilots' early retirement scheme, had been scheduled to last for 24 hours (see news, March 17).
It is currently affecting Lufthansa flights throughout Germany. Services with the airline's Eurowings and Germanwings subsidiaries are running as normal.
Bettina Volkens, Lufthansa's director of industrial relations, called today's strike "completely disproportionate".
While today's walkout is affecting short-haul services, tomorrow's will affect long-haul services.
The strike is the latest in a series of walkouts called by the Vereinigung Cockpit union, which is protesting plans to change the current scheme that sees pilots retire at 55 and retain some of their pay until they reach the state pension age.
Lufthansa said it has made concessions in recent talks, including giving the pilots a 5 per cent pay rise.
The frequent strikes by Lufthansa — and Air France — pilots are the result of the long-established carriers clashing with unions as they try to cut costs to compete with budget airlines.
Earlier this month, Lufthansa said it lost €232 million last year due to ten such strikes.