All flights were cancelled at Germany's Berlin Brandenburg Airport on Wednesday, the operator said, as staff went on strike for the day to press pay demands.
About 300 take-offs and as many as 35,000 passengers who were scheduled to pass through the airport were affected by the strike, which began at around 3:30 a.m. local time and lasted throughout the day.
While the airline authorities have rescheduled some flights for Thursday and diverted others to airports such as Dresden and Leipzig, many passengers have also been rebooked on trains.
It is the first time since 2018 that a strike has affected so many flights in Germany.
The labor strike was organized by the trade union Verdi, which called on airport staff in ground services, aviation security and at the airport company to strike in the wage dispute. It called the one-day work stoppage over what it said was insufficient progress in the three parallel wage talks.
The trade union is demanding a per month hike of 500 euros in the salaries of airport employees and the ground handling services over a 12-month collective bargaining contract.
However, during negotiations the airport company had made a collective bargaining offer for a 24-month term under which salaries would increase by three percent on June 1 and by another two percent on May 1 next year.
"When you see how high the inflation rate is and consider that the colleagues from this area have not had a salary increase for many, many years, this offer is of course a slap in the face for the colleagues," said union representative Enrico Ruemker, adding he hopes the pressure now is enough and their goal is movement at the negotiations.
Lufthansa chief Carsten Spohr criticized the strike.
"To call a one-day strike a warning strike is already unusual," he said.
The German government was set on Wednesday to release its annual economic report. A source told Reuters that a draft of this report forecast six percent inflation this year and 2.8 percent for 2024.
(With input from Reuters)