Police have closed entrances to the airport in the German city of Hamburg amid chaos caused by a strike.
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 ($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.