Seven major German airports have been brought to a standstill after hundreds of ground crew walked out on strike in a row over pay, the BBC reports.
Aircraft are grounded at Frankfurt, Munich, Stuttgart, Bremen, Hamburg, Hanover and Dortmund.
More than 2,300 flights have been cancelled affecting 300,000 passengers, with air travel effectively wiped-out.
Members of the Ver.di union and Civil Service Association are demanding a 10.5% pay increase for workers.
At Leipzig Airport, a handful of international flights got away this morning but domestic flights were cancelled.
At Frankfurt Airport, a couple of passengers wheeled suitcases through what is usually the bustling departures terminal. It was, one local TV reporter noted, almost as empty as it had been during the Covid pandemic.
The action coincided with the start of the high-profile gathering of world leaders and defense experts at the Munich Security Conference.
The arrival of prominent guests was not expected to be affected but other delegates were advised to travel by train.
Airports handling emergency aid for earthquake victims in Turkey and Syria have said that those cargo flights would continue as scheduled.