Lufthansa has already halted flights in Frankfurt, Munich and Berlin
German airline Lufthansa said on Thursday it has cancelled more than 670 European flights owing to warning strikes by ground staff and other divisions within the group.
Already on Wednesday, Lufthansa had said it would cancel most of its domestic and short-haul flights between 0500 hrs and midday (0400-1100 hrs GMT) at the airports of Frankfurt, Munich, Duesseldorf, Berlin, Hamburg and Cologne as well as several other locations.
The giant services sector union Verdi has called for walkouts to increase the pressure on management ahead of a second round of pay talks for around 33,000 ground staff and staff of the subsidiaries Lufthansa-Systems, Lufthansa Service Group (LSG), Lufthansa Technik and Lufthansa Cargo on Friday.
Verdi is demanding a pay increase of 5.2 percent plus job guarantees.
Lufthansa management had offered zero-wage increases for two years and longer working hours, an "affront to all Lufthansa employees," the union said.
The airline said that because passengers had been informed about the strikes a day earlier, there were no long queues at the airports on Thursday.
Verdi spokeswoman Christine Behle told the German news agency DPA that the conflict would likely drag on for some time, as no agreement was likely as early as Friday.