Hundreds of flights were cancelled at Germany's Dusseldorf and Cologne/Bonn airports on Monday due to a fresh strike by security personnel.
The one-day "warning strike" will continue until midnight at both airports, the ver.di trade union said in a statement.
"We have not received any acceptable offer so far in the negotiations, and now with the strike, the employees are jointly putting pressure on the respective employers," the ver.di representative Andrea Becker said in a statement.
In Dusseldorf, over 200 flights were canceled, and the operator advised passengers to check the current status of their flight online before traveling to the airport.
The strike forced Cologne/Bonn airport to halt almost all operations, and 134 flights scheduled for the day were canceled.
The ver.di trade union is demanding a 10.5% pay rise to help public sector employees beat inflation, but the previous round of negotiations have ended without agreement.
Besides airport security staff, public sector employees at local transportation, day-care centers and hospitals are staging walkouts on Monday in the North Rhine-Westphalia.
