Ryanair Holdings Plc accused Poland of discrimination amid an ongoing dispute between the government and the country’s air traffic controllers.

The airline filed a complaint with the European Union against Poland, saying that the local regulator is breaking the bloc’s rules by unfairly prioritizing national carrier PLL Lot SA.

According to Ryanair, its Polish competitor is favored by route selections, when a protest by air controllers starting on May 1 will limit flights to and from the east European country.

Poland “arbitrarily” selected priority connections, cutting most served by budget airlines including itself and Wizz Air Holdings Plc, Ryanair said in an email on Tuesday. The Irish carrier has become the biggest airline in Poland, flying 2.46 million passengers, or 34% of all traffic, in the third quarter of 2021.

Poland’s Civil Aviation Authority imposed limits on operations at Warsaw airports from the start of next month. Due to staffing issues, flights will be limited to between 9:30 a.m. to 5 p.m. 

The regulator selected 32 priority flights that can be carried out without curbs, 19 of which are serviced by Lot. Ryanair said Polish rules are due to disrupt plans of 11,000 passengers a day.