Hundreds of flights were cancelled again across Germany on Thursday as flight crew at flag carrier Lufthansa held a further round of strikes.
At the country's largest airport in Frankfurt, operator Fraport said 656 of 1,313 scheduled take-offs and landings were cancelled, with the overwhelming majority attributable to Lufthansa.
An attempt at arbitration in the deadlocked pay negotiations for pilots failed on Wednesday. Lufthansa and the pilots' union Vereinigung Cockpit (VC) were unable to even agree on a list of issues to be resolved.
The employees' protests overshadowed a ceremony marking the centenary of the German airline.
Flights were cancelled at the main Lufthansa airline, as well as subsidiaries Lufthansa Cargo and Lufthansa Cityline.
At the low-cost airline Eurowings, strikes were scheduled only for Thursday, while further industrial action was likely at the group's other German airlines on Friday.
A company spokesman said Eurowings is managing to operate more than 70% of its scheduled flights. While only part of the fleet is subject to German strike law, a three-digit number of pilots on German aircraft have also volunteered for duty.
