AUSTIN (KXAN) — Dozens of Southwest Airlines flights in and out of Austin-Bergstrom International Airport were still delayed Monday night.

“We have been delayed three times now, today,” said Anna Rounds, trying to get back home to St. Louis on Southwest Airlines.

The airline canceled 10% of its scheduled flights earlier in the day.

Rounds says her flight to Austin was also delayed for seven hours.

“We want to be able to get to the place we’re traveling to on time, and we also want to be able to make it back home to our lives and continue reality,” she said.

Both the company and its pilot union say disruptions don’t have to do with their vaccine mandate for employees. On Monday, the airline said “out-of-place aircraft and continued strain on crew resources” forced another day of delays and cancelations.

“Whether or not that is the key to say, what’s going on with Southwest remains to be seen, but to me, it just seems a little bit odd that we’re seeing those kinds of cancelations and problems,” said Carson Pearce, aviation director and associate lecturer at Texas A&M Central Texas.

He believes the widespread disruptions may have something to do with Southwest’s new COVID-19 vaccine requirement. On Friday, the airline’s pilots association asked a federal court to block it.

“I was talking to one of my graduates the other day. He has until, I think it’s early December, before he has to make a decision to turn down his $250,000-a-year job, because he’s, for personal reasons, deciding not to take it,” Pearce said.

Several Texas-based airlines are requiring employees to be vaccinated against COVID-19. Dallas-Fort Worth-based Southwest has set a Dec. 8 deadline. American Airlines, also based in Dallas-Fort Worth, has set it for Nov. 24.

United Airlines’ deadline passed with 99% of employees vaccinated, but nearly 600 people failing to comply with the mandate. Company officials say the workers can save their jobs by getting the shots before their formal termination meetings.

Delta does not have a vaccine mandate. On its website, the airline says it has a robust testing and vaccination program.

Pearce says those upcoming vaccine deadlines for Southwest and American Airlines may mean more disruptions to travel through the holiday season.

“There’s a lot of pilots that are in a holding pattern, weighing their options,” Pearce said.

He explains many still think of COVID-19 vaccines as ‘experimental’ and worry a long-term effect would put their physical pilot requirement in jeopardy.

“They’re looking at all the different ins and outs of, ‘what is the long-term effect from the physical side,’ because the pilot has to have that physical in order to be able to continue to fly long-term,” Pearce said.

The Centers for Disease Control and Prevention says historically, side effects usually happen within six weeks of receiving a vaccine dose.

“Serious side effects that could cause a long-term health problem are extremely unlikely following any vaccination, including COVID-19 vaccination,” its website reads.

The agency adds the U.S. Food and Drug Administration required each of the authorized COVID-19 vaccines to be studied for at least eight weeks after the final dose.

“Millions of people have received COVID-19 vaccines, and no long-term side effects have been detected,” the website says.

Pearce says some of his former students say they may start flying private or luxury, corporate planes to avoid their employers’ vaccine requirements.

“That will, indeed, have an impact on the availability of crews for aircraft,” he said.

A turbulent post-pandemic recovery

All this, Pearce says, is happening on top of staffing issues for more than a year. He says when the pandemic first hit, and flyers lost confidence, many airline staff took early retirements or were furloughed. It’s been hard to catch up.

“The airlines were kind of caught short, because they had all of the retirements, they had all of the layoffs,” Pearce said. “And when a pilot is not flying or in training, then they get rusty, they get behind — what we call, ‘get behind the power curve,’ and they have to go back in and start doing that.”

Another expert, Daniel Burnham with Scott’s Cheap Flights, agrees and thinks that’s part of what Southwest is going through now.

“When you have a shortage of these highly-trained employees who work throughout the value chain there, it’s difficult to ramp up operations quickly when people like us want to start flying again,” he said.

Pearce recommends flyers have a backup travel plan for the holidays.

Rounds says she wouldn’t fly Southwest Airlines again and maybe not fly at all, so she doesn’t have to rely on an airline.

“Maybe driving, even,” she said. “It’s a little bit more of an inconvenience just because the timing isn’t there, but it would be easier.”

Southwest Airlines said on Monday it didn’t have specific airport numbers to share, but there were fewer disruptions Monday than there were over the weekend. It also reiterated “operational challenges were not a result of Southwest Employee demonstrations.”