Hundreds of flight cancelations swept across the United States over the weekend because of a labor strike at the Canadian airline WestJet, and Texas airports are feeling the effects.

WestJet canceled 495 flights in the U.S. on Sunday as a work stoppage went into effect due to floundering negotiations between the airline and cabin crew union, according to the live FlightAware tracker. Four flights were canceled at Houston’s George Bush Intercontinental Airport, and while the figure was a fraction of the nationwide cancelations, it was still leading all other airlines in the city by that metric, according to FlightAware.

“We’re disappointed to be here, this directly impacts the travel plans of our guests, our WestJetters and the communities and businesses we serve,” Alexis von Hoensbroech, the CEO of the WestJet Group, said in a statement on Sunday. “Our focus remains on staying available for the union to reach an agreement. 

The airline said it started canceling flights at 10 p.m. Friday after the union issued a notice of a 72-hour strike the day before. The number of cancelations surged from 80 on Friday to more than 300 Saturday so the airline could avoid stranding guests and ensure “complete control” of operations, according to WestJet. 

The WestJet Component union represents more than 4,700 cabin crew members and has pushed for higher wages, an end to unpaid work and improved scheduling protections, according to its website. The union announced its strike early Sunday morning and had previously warned that would happen without an agreement in place beforehand.

The airline and union did not immediately respond to a request for comment.

Von Hoensbroech said WestJet’s recent proposal would have ensured a double-digit wage increase in one year, made the airline the only one to “offer an hourly rate covering all time before and after flights” and addressed other union priorities. She said the offer was not accepted.