Southwest grounds more than 360 flights

DALLAS — Southwest Airlines canceled several hundred more flights Monday following a weekend of major disruptions that it blamed on bad weather and air traffic control issues. Both the company and its pilots’ union denied reports of a sickout to protest mandatory COVID-19 vaccinations.

Southwest canceled more than 360 flights — 10% of its schedule for the day — Monday, and more than 800 others were delayed, according to the FlightAware tracking service.

Shares of Southwest Airlines Co. briefly fell more than 4% before a partial recovery; they were down 3% by afternoon.

The widespread disruptions began shortly after the Southwest Airlines Pilots Association asked a federal court Friday to block the airline’s order that all employees get vaccinated against COVID-19. The union said it doesn’t oppose vaccination, but it argued in its filing that Southwest must negotiate before taking such a step.

The union denied reports that pilots were conducting a sickout or slowdown to protest the vaccine mandate, saying it “has not authorized, and will not condone, any job action.”

The pilots association offered another explanation: It said Southwest’s operation “has become brittle and subject to massive failures under the slightest pressure” because of a lack of support from the company. The union complained about the “already strained relationship” between it and the company.

Airlines convinced thousands of workers to take leaves of absence in the pandemic. Unions at Southwest and American have argued that management was slow to bring pilots back, leaving them short-handed.