The cancellation rate of U.S. scheduled domestic flights hit 5.4 percent in December 2022, higher than the 1.1 percent rate reported in each November 2022 and December 2019, and higher than the 2.4 percent reported one year prior, according to the U.S. Department of Transportation monthly consumer report. 

The increase can be attributed in part to a significant storm at the end of December, with Southwest Airlines in particular requiring time to get operations back up to speed.

Southwest accounted for 54.5 percent of the December cancellations. The carrier canceled 14,042 flights from Dec. 24 to Dec. 31, which was 72.3 percent of the total flights that reporting carriers canceled during that time, according to DOT. For the month, Southwest led with 14.6 percent of its December flights canceled, followed by Alaska Airlines at 7.6 percent and Allegiant Air at 5.3 percent.

This week at a J.P. Morgan conference, Southwest CEO Bob Jordan shared results of a third-party study of that period, citing two major factors for the operational difficulty: the storm, and the closure of the Denver and Chicago Midway airports, where the carrier has about 25 percent of its crew base. 

As for consumer complaints, there were so many filed in December 2022 against airlines and travel agencies that they couldn’t be counted in time for the monthly consumer report, DOT announced Thursday. December and full-year 2022 consumer complaint data will be available in early April, according to the agency.

U.S. airlines operated more than 547,000 flights in December, down 3.4 percent year over year and down 2.5 percent from November 2022. That figure also is about 81 percent of the flights operated in December 2019.

For the month, U.S. carriers handled 40.4 million bags and posted a mishandled baggage rate of 1.1 percent per 100 bags enplaned, higher than the rate of 0.51 percent in November 2022 and higher than the 0.66 percent in December 2019. Of the industry-wide rate, 26.7 percent of the mishandlings were attributed to Southwest, followed by American Airlines with 21.9 percent, according to DOT. 

For the full year, carriers posted a mishandled baggage rate of 0.64 percent, higher than the 2021 rate of 0.51 percent and 2019 rate of 0.59 percent. 

Bumping, or oversales data, is reported quarterly rather than monthly. For the fourth quarter of 2022, the 10 U.S. reporting marketing carriers posted an involuntary denied boarding rate of 0.30 per 10,000 passengers, higher than the rate of 0.23 a year prior and higher than the rate of 0.16 percent from Q4 2019. The full-year bumping rate for 2022 was .32 per 10,000 passengers, higher than the rate of 0.17 a year prior and higher than the pre-pandemic rate of 0.24. 

RELATED: DOT: November Air Travel Complaints Up From October