Airline passengers in Germany's most populous state, North Rhine-Westphalia, face another day of chaos Friday following a strike by security staff.
The state's two main airports in Dusseldorf and Cologne-Bonn said they had together cancelled about 80 flights as the strike entered a second day amid a warning from union officials of unlimited industrial action.
While Dusseldorf, which is Germany's third biggest airport, cancelled more than 50 flights, 26 were cancelled at Cologne-Bonn.
This included flights from Germany's two biggest airlines - Lufthansa and Air Berlin.
About 24,000 passengers had been expected to depart Dusseldorf on Friday.
Long queues formed at terminals at both hubs from early morning after service sector union Verdi called the industrial action Thursday over a pay dispute for those working in the security sector.