An airline group, representing six major airlines and parcel services, filed a lawsuit aiming to block the Port of Seattle from implementing a pay increase that would make Seattle-Tacoma airport workers some of the highest paid in the country.

Reuters reports that Airlines for America filed the suit to prevent the Port commission, which runs Seattle-Tacoma airport, from increasing airport workers’ pay to $11.22 per hour in January and to $13 per hour in 2017.

The suit, which was filed in district court in Seattle, argues the wage hikes conflict with state and federal law and labor agreements.

“The rules, unless restrained, will cause irreparable harm to Airlines for America’s member air carriers,” the complaint states.

The industry group includes American Airlines Group, Delta Air Lines and United Airlines Inc. along with delivery services United Parcel Service Inc and FedEx Corp. The suit was joined by Baggage Airline Guest Services, an airport contractor that provides luggage handling and wheelchair escorts to travelers.

The Port commission maintains that it acted within its authority when they passed the pay increase measure back in July, in part to reduce employee turnover rates.

“We have worked closely with tenants and operators to hear concerns and provide guidance on implementing the policy,” airport spokesman Perry Cooper tells Reuters.

Seattle is among a number of cities that have pushed for raise wages above the current federal minimum of $7.25 per hour.

In fact, voters in SeaTac, where the Seattle-Tacoma airport is located, approved an initiative last year that increased the minimum wage for many workers to $15 per hour. However, airport employees were later excluded from the increase by a court order.

U.S. airlines sue Port of Seattle over airport workers wage hikes [Reuters]