Most of Germany's major airports have been hit by a ground-handlers' strike with more than 400 flights being cancelled and passengers shifted to different flights from those booked.
Lufthansa, Germany's biggest airlines, has cancelled nearly 430 flights and delays are expected to continue throughout the day even after the strike ends because of the spillover effect.
Members of the Verdi union are on strike for better pay and working conditions. With baggage-handlers, ground transport crew, technicians, security personnel and administrators taking part in the strike across the country, normal functioning of major airports was expected to deteriorate further as the dispute continued.
The main airports affected are Frankfurt, Munich, Düsseldorf, Cologne/Bonn, Stuttgart and Berlin (both Tegel and Schönefeld).
"German airport's on strike, we're going to be switching to a much later flight to a different airport," Dul @DulJuice tweeted.
Vicky @mummavic said: "Nothing like a good German airport strike to start my day hmmmmm! I sense it may be a busy one!!".
Meanwhile a Twitter message from Frankfurt airport indicated that the strike would end on Tuesday afternoon.
"Since we've made a substantial offer, it is not justifiable to maltreat the population with these strikes," the Local, a German English-language news website, quoted interior minister Hans-Peter Friedrich saying.