Airlines canceled hundreds of flights at German airports on Tuesday as ground staff workers went on strike over demands for more pay.
The nationwide strike by service workers severely disrupted air traffic throughout the country with a third of flights canceled out of Frankfurt, Germany's busiest airport.
Fraport AG, the company that operates the Frankfurt hub, said about 455 flights were canceled as members of the Verdi union walked out ahead of Wednesday's wage talks.
National airline Lufthansa said it had scrapped over 400 flights scheduled for Tuesday, primarily out of Frankfurt. The airline typically operates a total of 1,850 flights per day out of Germany and is the largest airline in Europe by passenger numbers.
The smaller Air Berlin scrapped 23 flights on Tuesday.
Though Frankfurt, the third-busiest airport in Europe, saw the biggest disruption, airports in Munich, Dusseldorf, Stuttgart, Cologne-Bonn, and Hannover were similarly affected.
The walkouts are part of a wider industrial action by public sector employees in Germany. The service workers union Verdi demands a 6.5 percent pay raise for its two million members. In early talks, the union rejected an offer of a 3.3 percent pay increase over 24 months.
Further negotiations are scheduled to take place on Wednesday but more strikes may follow soon.
Verdi argues that public sector workers' pay has been tightened by national and local governments trying to keep spending down. They further argue that their work is undervalued. If talks this week are unsuccessful, the dispute could go to mediation. If mediation fail, Verdi head Frank Bsirske has warned of broader strikes in the second half of April.
German Interior Minister Hans-Peter Friedrich called the union's action disproportionate.
Given that we have made a substantial offer, mistreating the public with these strikes is not justified, Friedrich told the Rheinische Post daily.
The strike has also affected public transport, hospitals, nursery schools, and local government services in the German state of Rhineland-Palatinate.
The disruption at Frankfurt Airport follows earlier industrial actions by the GdF labor union in February. Fraport said the strikes by GdF cost them around €4 million ($5.3 million) while Lufthansa put the figure around at least €10 million ($13.3 million).
There's no word on what the financial impact of the latest strike could be.