Speculation swirls over possible 'sickout' as Southwest Airlines abruptly cancels more than 1,800 flights

Thousands of Americans were left stranded at airports nationwide over the weekend after Southwest Airlines abruptly canceled nearly 2,000 flights.

What happened?

Southwest Airlines, one of America's most popular airlines, canceled more than 1,000 flights on Sunday after canceling more than 800 flights on Saturday, the Washington Post reported. Another 1,500 flights had been delayed.

The airline claimed the unusual delays caused by air traffic control and weather issues.

"[Air Traffic Control] issues and disruptive weather have resulted in a high volume of cancellations throughout the weekend while we work to recover our operation. We appreciate your patience as we accommodate affected Customers, and Customer Service wait times are longer than usual," Southwest Airlines tweeted on Saturday.

What did the FAA say?

The Federal Aviation Administration confirmed there were some ATC staffing and weather issues — on Friday, not Saturday. Otherwise, the agency blamed airline logistical issues for the canceled flights.

CNBC reported:

The Federal Aviation Administration said there were a "few hours" of flight delays on Friday afternoon because of severe weather and staffing issues at Jacksonville Air Route Traffic Control Center, which controls airspace in five parts of Alabama, Georgia, Florida, North Carolina and South Carolina.

"No FAA air traffic staffing shortages have been reported since Friday," the FAA said. "Some airlines continue to experience scheduling challenges due to aircraft and crews being out of place. Please contact the airlines for details about current flight schedules."

Is it something more?

As tens of thousands of Americans were left stranded at airports over the abrupt flight cancelations, the mass flight cancelation — which did not impact other air carriers — was speculated to be related to a "sickout," or protest over COVID-19 vaccine mandates.

Reporter Leland Vittert said federal employees were protesting a COVID-19 vaccine mandate.

Interestingly, the mass flight cancelations began one day after the Southwest Airlines Pilots Association filed a request in federal court to temporarily block a COVID-19 vaccine mandate.

The Southwest Airlines Pilots Association, however, denied the flight cancelations were related to action taken by Southwest pilots.

The SWPA said that while it was aware "operational difficulties affecting Southwest Airlines ... we can say with confidence that our Pilots are not participating in any official or unofficial job actions."

"Our Pilots will continue to overcome [Southwest] management's poor planning, as well as any external operational challenges, and remain the most productive Pilots in the world," the union added, the Post reported.