Southwest Airlines (NYSE:LUV) shares lost altitude on Thursday after the carrier posted a big miss on already reeled-in bottom line expectations.

For the fourth quarter, The Texas-based carrier reported a $0.38 adjusted loss per share, significantly greater than the $0.11 loss per share expected by the Street. The loss came despite record Q4 revenue of $6.2B that exceeded the consensus expectation of $6.14B.

Management explained that an $800M loss related to flight delays and cancellations in December was recognized by the company, igniting the larger than anticipated loss.

“With regard to the operational disruptions, I am deeply sorry for the impact to our Employees and Customers. We have swiftly taken steps to bolster our operational resilience and are undergoing a detailed review of the December events,” CEO Bob Jordan said. “In addition, our Board of Directors has established an Operations Review Committee that is working with the Company’s Management to help oversee the Company’s response.”

A third party review of December’s operational disaster is also anticipated. The airline is also subject to a DOT investigation regarding the high level of cancellations.

Moving forward, management warned operational issues remain an overhang on results.

“Thus far in January 2023, the Company has experienced an increase in flight cancellations and a deceleration in bookings, primarily for January and February 2023 travel, which are assumed to be associated with the operational disruptions in December 2022,” an SEC filing disclosed. “As a result, the company currently estimates a negative revenue impact in the range of $300M to $350M in first quarter 2023.”

While Jordan added that booking trends for March 2023 show some improvement, the carrier expects another net loss in the first quarter. Analysts had expected $0.19 in earnings per share.

Shares of Southwest Airlines (LUV) slipped 2.9% in premarket trading on Thursday.

Dig into the details of the results.