According to Reuters, Verdi union is in informal talks with Lufthansa, trying to reach an agreement to put an end to a strike over pay which started on Monday, causing more than 100 flight cancellations.

Earlier, the German-based airline said it would cut 128 flights per day until Monday in response to the walkout by technical and catering staff. Customers were alerted that they would face disruption over the weekend, in the middle of the holiday season. Today, Europe’s leading airline canceled more flights, including 28 long-haul flights from its hub in Frankfurt, Duesseldorf and Munich.

The majority of the cut flights were to European destinations.

An estimated 5,000 members of the German service trade union Verdi entered the strike’s fourth day. In order to reduce the impact of the walkout, Deutsche Lufthansa attempted to reassign non-striking staff to other duties.

Analysts estimated the cost of the walkout at about 5 million Euros ($7.81 million) per day for Lufthansa, one of the world’s largest airline companies.

Verdi negotiator Erhard Ott said Monday that the strike’s aim was to be prejudicial to the company rather than to lead to a large number of flight delays and cancellations. Verdi, representative for 52,000 air industry workers, requires a 9.8% pay rise for one year. The company is offering 6.7% over 21 months and a one-time payment.