Flights to Poland’s capital Warsaw could be severely limited from May 1 amid a dispute with air traffic controllers over pay and working conditions.

The country’s government said that Warsaw Chopin (WAW) and the smaller Modlin (WMI) airport to the north of the city would only be operational between 9.30 a.m. and 5 p.m., which will lead to the suspension of about 300 flights a day.

It comes after 180 out of 206 controllers working in Warsaw chose to resign rather than accept new conditions. The notice period for 136 of those ends on April 30.

An act issued by Prime Minister Mateusz Morawiecki contains the list of 32 destinations that will have priority operations should the restrictions on WAW and WMI come into force. These include London Heathrow (LHR), Frankfurt (FRA) and Paris Charles de Gaulle (CDG). The order also gives flights out of Chopin priority over those out of Modlin.

Ryanair said on April 26 that it has already complained to the European Commission about the decision because it believes the prioritized destinations unfairly favors LOT Polish Airlines. The Irish ULCC, which uses Modlin, claimed it would be forced to cancel 55 of its 57 routes to Warsaw as a result.

“The list inexplicably excludes destinations served by Ryanair from Warsaw Modlin, such as Stockholm and Milan, but includes LOT’s routes to Berlin and Vilnius, which can easily be reached by train or road in just a few hours,” the carrier said in a statement.

It added that both Ryanair and Wizz Air would only be allowed to operate two routes each from Warsaw during May, while LOT will operate 19 routes “including Rzeszow and Szczecin which are clearly not essential for air connectivity from Warsaw.”

However, LOT said the order means it would be forced to cancel up to 75% of its scheduled flights or change the flight hours.

The restrictions on routes into and out of Warsaw could see airlines turn to other nearby airports such as Lodz (LCJ), located about 140 km southwest of the Polish capital.