Passengers travelling through Germany's Duesseldorf and Cologne airports faced a second day of disruption on Friday as security personnel continued a strike over pay.
More than 100 flights were cancelled at the two airports, with Germany's largest airline Lufthansa scrapping over 80 flights at Duesseldorf alone.
Trade union Verdi has called for a 33 percent increase in pay for around 1,000 security personnel employed by private firms at the two airport.
It says the majority of security staff in the German state of North Rhine-Westphalia, where the two airports are located, are on hourly pay of 8.23 euros ($11) and wants that increased by 2.50 euros to pull workers out of the low pay sector.
The BDSW association representing the security firms has called the pay demand "completely excessive" and said the strike is out of proportion. It has offered a pay increase of 9.22 percent.
Verdi has said the strikes could go on indefinitely and could be extended to include other staff and security personnel in a show of solidarity.
The strike had already resulted in around 200 flights being cancelled on Thursday.
Duesseldorf is Germany's third largest airport after Frankfurt and Munich.
($1 = 0.7477 euros)
(Reporting by Victoria Bryan and Peter Maushagen; Editing by Alison Williams)