The airline's executives told employees in late September that the operation had been stable since mid-August. On-time performance, a dismal 62% in June, was back up over 80% in September.
The momentum was short-lived.
Southwest fell apart again over the weekend, canceling more than 1,900 flights Saturday and Sunday. On Sunday, a busy fall break and holiday weekend travel day, the airline axed 30% of its flights, stranding travelers across the country. Monday cancellations were a fraction of weekend levels, but Southwest still led all carriers in cancellations, with more than 350.
By Tuesday morning, cancellations were down to 2% for the day, though still leading other domestic carriers, according to FlightAware, which tracks both cancellations and delays.
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►Five-hour wait times, flight shopping and a rental car rush: Southwest cancellations send travelers scrambling
The airline blamed air traffic control issues and weather in Florida on Friday, saying the ripple effects put planes and employees out of place, and it had too few reserves to pick up the slack. Southwest caters to vacationers, and Florida is a key cog in its operation.
Southwest and its pilots union have steadfastly denied that workers walked off the job to protest a federal vaccine mandate. (The pilots sued the airline to stop the mandate.)
"It was a very difficult weekend for many of you, and I’ve seen speculation on the reasoning," Southwest CEO Gary Kelly told employees in his first public comments on the meltdown Monday. "The fact is the Florida weather on Friday and unexpected ATC issues on Friday night resulted in delays and cancellations across our network, and it just got us behind."
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Kelly reiterated that the cancellations were not related to vaccine mandates in a Tuesday interview with CNBC.
"We look at all of our employee behaviors in terms of absenteeism ... and they're all very normal," Kelly said. "The president of our pilots union has been out talking to the media confirming all of that, so I think people, again, that understand how airlines work, when you get behind, it just takes several days to catch up."
White House press secretary Jen Psaki also denied allegations that vaccine mandates affected Southwest flights.
"I know there was a little hubbub over the course of the last few days about Southwest Airlines," Psaki said during a Tuesday press briefing. "We now know that some of those claims were absolutely false and actually the issues were completely unrelated to vaccine mandates."
Jon Jager, an analyst with aviation data firm Cirium, said a confluence of events crippled Southwest.
"They were just caught in a perfect storm,'' he said, citing staffing levels, weather and flight crews running out of time because of the delays and cancellations. Pilots and flight attendants are only allowed to work a certain number of hours per day due to contract and government rules.
Southwest isn't alone in struggling during the spike in travel after the COVID-19 vaccines were made widely available. American Airlines had a slew of troubles during Father's Day weekend, and Spirit Airlines had a seven-day string of cancellations in late July and early August that stranded passengers and cost the airline about $50 million.
But Southwest has had more frequent problems, damaging its carefully crafted reputation as a reliable airline. For months, it's said it is working on fixes. The biggest push: hiring employees. Incoming CEO Bob Jordan says the airline is hiring 5,000 workers this fall and 8,000 next year, most of them to replace workers who took early retirement or extended leaves during the pandemic.
Here's what we know about Southwest Airlines' October meltdown
What happened over the weekend, and how will Southwest, which has cultivated enviable passenger loyalty in its 50 years, recover?
President and Chief Operating Officer Mike Van de Ven spoke with USA TODAY Monday afternoon to offer some answers.
Why was Southwest Airlines the only carrier slammed by the brief Florida ATC issues and weather?
"Florida is just a critical node in our network," Van de Ven said.
He said 40% to 50% of the airlines' planes flow through Florida nearly every day, and many crews change there.
"So when we have a disruption, a significant disruption, in Florida, it tends to spread to our entire network," he said. "And that was the situation that happened to us on Friday."
By Friday night, he said, the airline had "well over" 100 planes and crews "that weren't where they were supposed to be."
"That was the problem we were trying to solve," he said.
Was Southwest Airlines upfront about the reasons for the October meltdown?
Van de Ven said there is no evidence a work stoppage of any kind was to blame, citing the rate of sick calls and other measures the airline keeps an eye on.
"There's no indication in any of our data that there is anything going on nefariously with respect to any type of activity like that," he said.
Van de Ven went out of his way to praise the airline's flight crews and other employees for handling the weekend mess that also stranded them and left many without hotels. In 2019, for contrast, Southwest sued its mechanics over a work slowdown in a high-profile spat that caught the Federal Aviation Administration's attention.
What is Southwest Airlines doing for travelers after mass flight cancellations?
Southwest has yet to issue a public statement, on its website or elsewhere, to stranded travelers, but Van de Ven said the airline is sorry.
"We are very sorry about the impact we've had on their plans," he said.
Van de Ven said the airline has been flexible with ticket changes and refunds and is issuing goodwill vouchers and compensation for other expenses, but he declined to provide specifics.
Some travelers reported waits of several hours to reach the airline over the weekend and difficultly obtaining a refund.
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Will Southwest Airlines cancel holiday flights?
Southwest, like other airlines, has responded to flight problems this year by reducing its flight schedules to try to give it more breathing room while staffing remains tight.
The airline cut its planned fall flying, and Van de Ven said Southwest will review the rest of this year's schedule in the next two weeks with an eye toward proactively cutting flights if necessary.
Yes, that could include peak Thanksgiving and Christmas flights, despite efforts to keep those flights intact.
The question the airline will ask, he said: "On these peak holiday period travel days, do we have enough resiliency and recoverability if something unexpected happens?"
If something does happen, travelers would be notified and rebooked on other flights or offered a refund.
Longer term, the answer is more employees and more flights, he said, so Southwest can more easily rebook passengers when things go awry.
"The fix really is just trying to get Southwest Airlines to our normal level of trips and frequencies in our network, and that could take a while," Van de Ven said.
This article originally appeared on USA TODAY: Southwest cancellations: Why the airlines says it canceled flights