A one-day strike by workers at 13 German airports, including the Frankfurt and Munich hubs and all the country’s other main destinations, caused the cancelation of most flights on Monday.

Flight cancellations at Hamburg Airport after a surprise strike by workers affected more than 40,000 passengers on Sunday, a day before a planned wider protest across Germany amid new contract negotiations.

Strike action grounded thousands of flights in Germany on Monday, including all connections to and from Berlin, as the service sector union called on workers to walk out for better pay.The Verdi union said Friday it was calling on public sector workers and some 23,