No end date has been set for the current round of strikes by Lufthansa pilots, a spokesman for the pilots' union said on Friday, as the strike entered its third day. "There is no predetermined termination date for the strike," Joerg Handwerg, spokesman for the Vereinigung Cockpit (VC) union told dpa. He added that the aim was to extract a negotiable offer from the German carrier, so that the current round of stoppages could come to an end. Handwerg said the union had the backing of its members. "They do not expect us to treat Lufthansa with velvet gloves," he said.

Lufthansa says it will cancel 137 flights Saturday, affecting 30,000 passengers, amid an ongoing pilots' strike. The cancellations will include 88 intercontinental flights, the company says.

Germany's biggest air carrier has been locked in wage disputes with its pilots since 2014, prompting multiple strikes. The most recent began Wednesday and the pilots have refused to say when it will end. The strikes are beginning to affect Lufthansa's bottom line, with company stocks dropping 0.67 percent in Frankfurt during Friday trading.

VC has notified the authorities that it will hold a demonstration on Wednesday at Frankfurt Airport, the country's main hub with the aim of demonstrating unity behind the strike.

Handwerg declined to predict whether the current strike - the 14th in a series dating back more than two years - would continue that long.

On Friday, the third day of the current strike, domestic and European flights were worst hit and the travel plans of more than 100,000 passengers affected. The strike action has resulted in some 2,500 flights being cancelled over the past three days, affecting 315,000 passengers. VC has refused to enter into arbitration as called for by the company.

German airports, including the main hubs at Frankfurt and Munich, were reported to be quiet. Chaos was avoided by many Lufthansa passengers simply staying away from airports. The company was providing updated information on its website and arranging alternatives for stranded passengers.