Severe weather across Florida, where the airline has a widespread network, initially disrupted flights on Oct. 8, followed by unspecified air traffic control problems in the same region. Southwest canceled 30% of its flights Sunday, while another 32% were delayed, according to FlightAware, an online tracking service. About 24% of flights were delayed both Oct. 8 and Oct. 9.

“Although we were staffed for the weekend, we could not anticipate the significant disruption that was created from unexpected ATC issues and bad weather across our Florida stations,” Alan Kasher, the company’s executive vice president of operations, told employees in a message Sunday. “Irregular operations disrupt even the best plans and can make it difficult to recover the operation quickly.” 

Southwest’s weekend issues are similar to delays and cancellations over the summer that led to frustration on the part of travelers and its crews. Other airlines faced scheduling issues this summer, including American Airlines Group Inc. and Spirit Airlines Inc., but Southwest’s problems have persisted into the fall.  

Southwest pared an early drop as low as 4.3% to trade down 2.4% to $52.61 as of 9:58 a.m. in New York. The shares rose 16% this year through Oct. 8, trailing only American Airlines in a Standard & Poor’s index of the five largest U.S. carriers. 

Pilots weren’t part of the weekend problem, Casey Murray, president of the Southwest Airlines Pilots Association, said in a statement.

“I can say with certainty that there are no work slowdowns or sickouts either related to the recent mandatory vaccine mandate or otherwise,” Murray said in a statement. Under federal labor law, “our union is forbidden from taking job action to resolve labor disputes under these circumstances. SWAPA has not authorized, and will not condone, any job action.”

The union on Oct. 8 asked a court to temporarily block the company from carrying out federally mandated coronavirus vaccinations until an existing lawsuit over alleged U.S. labor law violations is resolved. The airline has set a Dec. 8 deadline for the shots, which the pilots claim “imposes new conditions of employment” and threatens termination. 

The union previously threatened to protest publicly during the upcoming winter holidays if scheduling issues at the carrier didn’t improve. 

“What was a minor temporary event for other carriers devastated Southwest Airlines because our operation has become brittle and subject to massive failures under the slightest pressure,” Murray said Sunday. “Our pilots are tired and frustrated because our operation is running on empty due to a lack of support from the company.”

In a statement Sunday on Twitter, the Federal Aviation Administration said that delays and cancellations “occurred for a few hours Friday PM due to widespread severe weather, military training, & limited staffing in one area of the Jacksonville en route center.”

Jacksonville Center handles high-altitude traffic over Florida and other nearby states.

The Dallas-based airline had ramped-up flights earlier this year to meet surging domestic demand, but was forced to cut its schedule for the last four months of 2021 due to staffing issues. More than 99,000 Southwest flight arrivals were delayed from June through August, in part because of worker shortages.

Southwest has struggled to hire 5,000 workers it wants to add this year, facing competition particularly for entry-level workers from retailers, shipping companies and others nationwide. It wants to add 25,000 employees over three years.

—With assistance from Alan Levin.

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