Passengers flying in and out of Berlin airports face delays or cancellations Monday due to a ground crew strike over pay, union officials said.
The latest stoppage comes just two days after a walk-out on Friday grounded more than 650 flights.
"Unfortunately, the employer did not react and made no negotiable offer, allowing the time over the weekend to go unused," said Enrico Ruemker, an official at Verdi.
Berlin ground crews had already walked out twice in February as service workers' union Verdi piles on pressure in wage negotiations.
The union is fighting for higher salaries for around 2,000 workers registering passengers and loading baggage at the airports.