Security personnel and other staff are staging strikes Monday at airports in Hamburg, Hannover and Stuttgart to press their demands for pay increases of up to 2.50 euros (USD 2.86) an hour.
German news agency dpa quoted Hamburg airport spokeswoman Stefanie Harder describing the situation at the airport as "catastrophic."
About a quarter of all flights there have been canceled. Officials in Hannover and Stuttgart warned of long queues for security at those airports too.