(new: Lufthansa flight attendants also ready to strike)

FRANKFURT (dpa-AFX) - With renewed warning strikes by several professional groups, the Verdi trade union is paralyzing important parts of German air traffic this Thursday. Passengers will have to prepare for hundreds of flight cancellations and delays. In addition to Lufthansa ground staff, aviation security staff in Frankfurt and Hamburg have also been called to strike. As a result, no passengers will be able to board flights at either airport on Thursday, according to the operators. The first flight cancellations were already due to take place on Wednesday evening, as the technical departments of the ground staff were due to go on warning strike earlier.

With the approximately 19,000 flight attendants of Lufthansa and its subsidiary Cityline, another professional group prepared to strike on Wednesday. The cabin crew union Ufo reported an overwhelming participation in the ballot, in which more than 96 percent voted in favor of industrial action. However, the sector union has not yet announced a strike date. A strike is still avoidable, said Ufo boss Joachim Vázquez Bürger. "We remain open to reasonable offers and fair solutions from the employer in order to possibly avert strikes in the short term."

Lufthansa CEO Carsten Spohr could send out public signals when he presents the MDax group's annual results this Thursday in Frankfurt. According to previous announcements, Europe's highest-revenue aviation group has continued to recover from the corona shock and, according to analysts, will report one of the highest operating profits in its history at around 2.7 billion euros.

Hamburg Airport had already canceled all 141 departures for Thursday on Tuesday evening due to the lack of security checks. According to the press office of Helmut Schmidt Airport, some of the planes would take off without passengers. This was necessary in order to avoid further disruptions to air traffic. The airport expects many rebookings for Friday, so that flights are likely to be very busy. However, due to the parallel train drivers' strike, there is no possibility of changing to the train, at least on short-haul routes.

Frankfurt Airport operator Fraport recommends that passengers contact their airlines and do not come to the airport under any circumstances. Originally, 1170 take-offs and landings with around 160,000 passengers on board were planned for Thursday at Germany's largest airport. A spokesperson for the airport said that it was up to the respective airline to decide which connections would be canceled. Airport operations will be maintained so that transit passengers can continue to transfer. Arrivals will also be possible in Frankfurt.

However, Lufthansa, the airport's largest customer, which accounts for more than two thirds of Frankfurt's traffic, will also be on strike by its own ground staff on the following day, Friday, until 7.10 a.m. on Saturday morning. The airline warned its customers for Thursday: "The security checks outside the transit area will be closed. Access to the departure area is therefore not possible. We therefore ask all guests who would like to start their journey in Frankfurt or Hamburg on March 7 not to come to the respective airport."

Screeners at other airports are not on strike. They are employed by private companies that check passengers, staff and baggage at the entrances to the security area on behalf of the Federal Police. In Bavaria, however, aviation security staff are part of the public service. Munich Airport will therefore remain open, and Lufthansa says it is trying to offer 10 to 20 percent of its original program. The warning strike by Lufthansa ground staff began in the technical areas on Wednesday evening and is to continue until 7.10 a.m. on Saturday morning.

The trade union Verdi has called on all Lufthansa ground staff - around 25,000 people - to take part in the warning strike. This is already the fifth wave of warning strikes in the wage dispute and the third with a direct impact on passengers. Verdi is demanding 12.5 percent more pay for a twelve-month term, while the company has so far offered 10 percent for a 28-month term. After four rounds of negotiations, an inflation compensation bonus of 3,000 euros is relatively uncontroversial.

The collective bargaining in aviation security concerns the working conditions of around 25,000 employees of private security service providers. Five rounds of negotiations in the wage dispute have so far failed to produce a result, with more than 1100 flights canceled during the first wave of warning strikes at eleven airports. Verdi is demanding an increase in hourly wages of 2.80 euros over a period of twelve months with faster overtime bonuses from the first hour of overtime. According to the employers from the Federal Association of Aviation Security Companies (BDLS), they have offered 2.70 euros in three stages over a period of 24 months./ceb/DP/stw