Pilots at Lufthansa, Germany’s flagship air carrier, are on strike over proposed cuts in early retirement benefits and other cost-saving measures. The work stoppage, which began Wednesday and is expected to continue Thursday, has grounded hundreds of flights across Europe.

Wednesday’s strike hit short- and medium-haul flights, while Thursday’s job action was scheduled to target long-haul and cargo flights. Lufthansa canceled about 750 flights Wednesday, Reuters reported. The cancellations, according to Deutsche Welle, affected about 80,000 passengers on domestic and European flights.

As it stands, Lufthansa pilots can retire at 55 and receive up to 60 percent of their pay until their regular pension kicks in a decade later, Deutsche Welle reports. The airline wants to increase the age at which pilots can opt for early retirement. For months now, Lufthansa and the union Vereinigung Cockpit, which also represents engineers, have failed to reach a resolution.

"Management maintains its position of worsening conditions for young pilots through the abolition of [the current retirement system]. This is not acceptable," said a statement from the union, translated from German.

Pilots have also expressed concerns over Lufthansa’s plans to expand its low-cost operations, as the carrier seeks to compete with popular, low-budget airlines like Ryanair and easyJet.

"It's very very important for Lufthansa to bring their costs down to a level at which they can continue to compete,” a private equity analyst told Reuters.

Labor struggles are increasingly familiar to Lufthansa. Last year, nearly a dozen strikes cost the company around $250 million. Air France-KLM has also faced walkouts in recent months.