Germany’s Verdi union has called on Lufthansa ground staff to strike from Tuesday morning. It’s the latest escalation in a wave of industrial disputes which have hit the country’s aviation industry already this year.

The German service union Verdi has called a strike of Lufthansa employees from 4 a.m. on Tuesday to 7:10 a.m. on Wednesday. Major international airports in the German cities of Frankfurt, Munich, Hamburg, Berlin, Stuttgart, and Düsseldorf are set to be affected, as is Cologne-Bonn. Around 900 out of 1,000 scheduled flights have been canceled, affecting around 100,000 passengers, according to Lufthansa.

The union has been involved in an ongoing dispute with the airline, calling for 12.5% pay rises and a one-off group-wide inflation bonus for 25,000 Lufthansa employees. Lufthansa last week increased its offer to a 10% pay rise, which was rejected by 96% of employees who don’t feel their wages match inflation in Germany, which was at 5.9% last year and 6.9% in 2022 but has now fallen considerably to 2.9%.

Marvin Reschinsky, the lead union negotiator, called basic hourly rates that can be as low as €13 ($14) per hour ‘really anti-social’ compared to pay rises offered to pilots. ‘We don’t want this escalation,’ he claimed. ‘We want a speedy result for employees and passengers.’

Lufthansa chief human resources director Michael Niggemann called the latest strike ‘disproportionate’ and said it disrupted both passengers and employees. ‘This is not the way to handle our joint responsibility to our colleagues, our passengers or for a strong and reliable Lufthansa,’ he said.

The next round of negotiations will take place on February 21. German airports were hit by a wave of strikes earlier this month when security staff walked out demanding higher pay. Over 1,000 flights were canceled across 11 major airports on February 1, impacting over 200,000 passengers. In January, airport ground and security staff went on strike in Hamburg and Berlin.