At the moment over 200 flights (115 departures and 90 landings) were canceled to and from Dusseldorf and 40 flights (35 departures and 5 landings) out of 190 were canceled in Cologne-Bonn airport.
The airports warned of possible delays and instructed passengers not to take hand luggage to make security checks faster.
The cancellations are due to a strike by German public services trade union Verdi.
Trade union representative Andrea Bekker noted Wednesday that the strike followed three rounds of unsuccessful negotiations with employers regarding wage increases.
The strike is planned to last until the end of the day.