The Thursday walkout has canceled 380 flights, disrupting air traffic from Düsseldorf, Cologne, Dortmund, Hannover, Stuttgart, Berlin, and Hamburg. While the routes within Germany bear most of the brunt, thousands of passengers traveling to and from other European countries were also forced to change their travel plans.

No long-haul flights were affected, according to the two companies.

Both Eurowings and Germanwings are low-cost carriers fully owned by Germany's flagship airline Lufthansa. The strike was prompted by the dispute between the UFO union and Germanwings over part-time work contracts for flight attendants.

"We regret that this escalation is necessary." UFO board member Nicoley Baublies said in a statement. "But negotiations reached a point at which there is no alternative to a strike."

DW reporter Milan Gagnon reported from the scene.

Carriers offer refunds

The 24-hour strike is expected to affect over 50,000 people. The two companies have offered their passengers the possibility to cancel or change reservations without extra costs.

Following UFO's announcement, the management slammed the walkout as "disproportionate" and said the dispute only affected a small number of workers.

"A call to strike because of a disagreement over temporary contracts is incomprehensible and absurd," Lufthansa spokesman Martin Leutke said.

Eurowings published a  full list of canceled flights on their website.

The mother company Lufthansa is trying to cut costs amid rising competition from Gulf state airlines and other budget carriers in Europe.

dj/kl (dpa, Reuters, AP)