FRANKFURT (dpa-AFX) - Warning strikes at several German airports have led to numerous flight cancellations since Thursday morning. The next warning strike by ground staff at Lufthansa, Germany's largest airline, has begun; it is expected to last until Saturday morning (7.10 a.m.). In addition, the air security controllers at several airports stopped work. Lufthansa intends to fly 10 to 20 percent of its original flight schedule during the warning strike.

Passengers will only be able to change trains to a limited extent: Deutsche Bahn train drivers have been on strike for 35 hours since Thursday morning.

According to the Verdi union at Frankfurt Airport, the Lufthansa strike got off to a very successful start. Passengers are unable to check in at the airport because the security checkpoint is also on strike. Security staff also went on strike in Hamburg, Düsseldorf and Koln/Bonn. At the two NRW airports, the industrial action began without notice - so the airport and its partners were unable to prepare for it.

All passengers who had planned a flight from Düsseldorf for Thursday were asked to check their flight status with the airlines or tour operators before their arrival, the airport said. In Koln/Bonn, cargo traffic in particular is to be severely affected, while passenger flights are not to be affected.

At Frankfurt Airport, several hundred strikers gathered in a parking lot for a rally on Thursday morning. "Our wages should also take off," read a poster attached to the stage. "We are worth it," read a banner on the building diagonally opposite. After the rally, a demonstration was planned at the Lufthansa building, where the company's annual press conference was taking place.

On Wednesday evening, Lufthansa's technical departments had already gone on their fifth wave of warning strikes, which were extended to the passenger-related areas in the terminal in the morning. In this way, Verdi wants to force management to make greater concessions in the ongoing wage negotiations for around 25,000 ground staff. The negotiations with the private aviation security companies also involve around 25,000 people.

Frankfurt: At Frankfurt Airport, no passengers wishing to depart from Frankfurt were able to enter the security area of the airport on Thursday due to the lack of security checks. Nevertheless, take-offs and landings took place so that at least transit passengers were able to change planes. It was also possible to disembark in Frankfurt.

Munich: Munich Airport was to remain open on Thursday and Friday despite the warning strike by ground staff, but many flights were expected to be canceled. According to the airport, around 500 of 800 flights were to be canceled on Thursday.

Stuttgart: At Stuttgart Airport, four Lufthansa flights each to and from Munich and Frankfurt were canceled due to the warning strike on Thursday, a spokeswoman for the airport announced on Wednesday.

Berlin: According to the flight schedule, many Lufthansa flights to and from Munich and Frankfurt were also to be canceled at the capital's BER airport on Thursday and Friday.

Hamburg: The airport operator has canceled all 141 departures for Thursday. According to the airport, 15 Lufthansa arrivals and 15 Lufthansa departures have been canceled for Friday.

Düsseldorf: At Düsseldorf and Koln/Bonn airports, almost all Lufthansa connections were canceled due to the Verdi warning strike, 13 other flights were canceled due to the unannounced strike by security personnel.

In the current wage dispute at Lufthansa, Verdi is demanding 12.5 percent more pay, but at least 500 euros per month for a period of twelve months. In addition, there is to be a uniform Group-wide inflation compensation bonus of 3000 euros. Lufthansa refers to past wage increases and has so far offered 10 percent more pay and the inflation compensation bonus for a period of 28 months. The next negotiations are scheduled for March 13 and 14.

Lufthansa passengers can also expect strikes by another professional group in the near future. A few weeks before the start of the Easter vacations, flight attendants at Lufthansa and its regional subsidiary Lufthansa Cityline voted in favor of strikes in a ballot held by the Ufo union on Wednesday. It remains unclear when strikes are to be expected.

According to Lufthansa, the ongoing warning strikes have cost the company around 100 million euros so far this year. In addition, numerous customers are holding back on bookings, said CFO Remco Steenbergen on Thursday at the presentation of the balance sheet in Frankfurt.

According to economic researcher Clemens Fuest, the ailing German economy is also suffering from the repeated strikes in air traffic and on the railroads. "This is an additional burden that we don't really need," said the head of the Munich Ifo Institute in the ZDF morning show. "The economy is shrinking, and if something like this happens on top of that, then there will suddenly be parts missing from production that can't be delivered, or people won't be able to get to meetings, or maybe not even to work."

Fuest added: "But it has to be said that the trade unions in Germany are very reasonable overall." In the past ten years, there have been four to five times as many strike days in France as in Germany./ceb/DP/nas