Nearly 400 flights at Frankfurt airport alone were canceled Wednesday morning after airport firefighters walked off the job. Public-sector workers doing ground handling, security checks and other jobs were also participating in the strikes affecting flights in Munich, Cologne, Duesseldorf, Hannover, Bremen, Berlin and Hamburg.
The ver.di union is looking for a 6 percent pay rise for its 2 million members, with negotiations scheduled to resume Thursday.
German Interior Minister Thomas de Maiziere called the strikes "completely disproportionate" and unnecessary, saying the government had offered an increase of 3 percent and other concessions, AP reported.
He says "we should talk about that first, before striking."