Southwest Airlines grounded its flights Monday night because of an issue with its weather data provider.
"While Southwest Teams and the vendor worked to restore connectivity, we implemented a ground stop to protect the Safety of our Crews and Customers," the airline said in a statement Monday night announcing flight operations had resumed.
The airline had tallied 1,398 delays — the most of any airline on the planet, according to Flightaware, a site that tracks global airline cancellations and other issues.
In replies to a barrage of complaints on its official Twitter page, airline representatives apologized to customers and said the company was working to resolve the problem “ASAP.”
Images showed a packed airport concourse in Phoenix and Southwest planes that appeared to be sitting on the tarmac in Denver.
“NEWS from my life,” tweeted Sheryl Gay Stolberg, a New York Times reporter. “On board a @SouthwestAir flight from Ft Myers to Baltimore but can’t take off. Been holding at gate for 45 minutes. Entire @SouthwestAir fleet grounded because the company’s weather monitoring system is down.”
Another said she had been delayed for more than three hours in Chicago. Hollywood Burbank Airport said it had suspended all Southwest departures over a “network” issue, though it later said the flights were taking off again.
Delta Airlines, meanwhile, said Monday that it was working quickly to address a “technical” issue making it difficult for customers to buy tickets.
Hollywood Burbank Airport reported a second nationwide issue with Southwest on Tuesday, but it appeared to be fixed within an hour, according to the airport's Twitter account. Southwest said it was aware of system issues and were "working quickly to resolve."