Aviation security staff at several German airports including Hanover will go on strike on Friday, the trade union verdi announced on Wednesday.
Verdi has already called for day-long strikes on Thursday by aviation security staff at five German airports: Hamburg, Stuttgart, Karlsruhe/Baden Baden, Cologne and Berlin.
Travellers will not be able to access the airport without the security workers, who are responsible for staffing checkpoints and examining passengers and luggage.
It remains unclear what airports besides Hanover will be affected by Friday's security staff strikes.
Thursday's aviation security strike is expected to force the cancellation of more than 580 flights at the five affected airports and cause additional delays, impacting around 90,000 passengers, according to estimates by the airport operator industry group ADV.
The industrial action by aviation security staff are the latest in a wave of strikes to hit Germany's transport sector in recent weeks.
Munich-based cabin crews at German airline Lufthansa are currently on strike, and Lufthansa ground crews recently staged strikes against the airline as well.
A strike against German national railway Deutsche Bahn by the GDL train drivers' union ended earlier early on Wednesday morning in a bitter fight for shorter working weeks.
Local public transport workers in much of Germany, meanwhile, held strikes last week to demand better working conditions.
