Southwest cancels more than 1,000 flights, Cruz says it’s Biden’s ‘illegal vaccine mandate at work’

The airline has blamed the cancellations on “disruptive weather” and air traffic control issues

Sen. Ted Cruz, R-Texas, took to Twitter late Sunday to speculate about Southwest Airlines’ decision to cancel more than 1,000 flights just days after its pilots’ union asked a court to block the company's new COVID-19 vaccination mandate.

The airline has blamed the cancellations on "disruptive weather" and air traffic control issues. Some Twitter users were suspicious of the timing of the disruption, including the Texas Republican.

"Joe Biden’s illegal vaccine mandate a work!" Cruz tweeted. "Suddenly, we’re short on pilots & air traffic controllers."

The airline announced last week that—due to the new rules from the Biden administration—its workers must be vaccinated against COVID-19 and have until Dec. 8 to be fully vaccinated. Workers are allowed to seek medical or religious exemptions.

Southwest said it has to mandate vaccines because of new rules from the Biden administration requiring companies with federal contracts to have vaccinated staffs. Southwest’s work for the government includes flying the military in emergencies and carrying mail for the U.S. Postal Service.

Last week, rivals American Airlines, Alaska Airlines and JetBlue told their staff they need to be vaccinated. United Airlines, in August, was the first major airline to do so and has since said that more than 97% of its workers have been vaccinated. United also said it would put staff who couldn’t get the shots due to medical or religious reasons on unpaid leave until COVID-19 rates go down.

The Southwest Airlines Pilots Association on Friday challenged the company’s mandate inside a Dallas federal court, claiming the policy "unlawfully imposes new conditions of employment and the new policy threatens termination of any pilot not fully vaccinated by December 8, 2021," according to Bloomberg.

The union issued a press release on Saturday stating that it is aware of the "operational difficulties" affecting the airline, but "we can say with confidence that our Pilots are not participating in any official or unofficial job actions."

A Southwest spokeswoman told CNBC in an email that claims that the COVID-19 mandate was the cause of the delay were "inaccurate."

"There’s a lot of unfounded rumor and speculation circulating," she said.

The airline did not comment on Cruz’s tweet, but pointed Fox News to the earlier statement on the weather challenges and air traffic control issues. 

"We’ve continued diligent work throughout the weekend to reset our operation with a focus on getting aircraft and Crews repositioned to take care of our Customers. And we’re working diligently to accommodate our Customers as quickly as possible, and we are grateful for their patience. We’re offering Customers added flexibility to explore self-service rebooking options on Southwest.com, where they can get updates on the status of their travel," the statement read.

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According to FlightAware, a website that tracks cancellations and delays, Southwest has canceled 1,018 flights and had 597 flights delayed on Sunday alone. On Saturday, the airline canceled 808 flights and had 1,187 flights delayed. 

Fox News' Tyler O'Neil and the Associated Press contributed to this report