Southwest Airlines has been named by one report as the best carrier in 2020 amid challenges the industry faced due to the coronavirus pandemic.

According to Wichita State University’s Airline Quality Report released Monday, Southwest maintained a nearly level score for 2020 despite nine other airlines seeing a decrease in their scores.

Southwest moved up to first place in 2020, after coming in third in 2019. Following behind is Allegiant Air, who was in first place in 2019; and Delta Airlines, who took the third spot after finishing fourth in 2019.

Wichita State’s report is based on data from the Department of Transportation tracking on-time arrivals, involuntary denied boardings, mishandled baggage and a combination of 12 consumer complaint categories.

While airlines overall had better on-time performance and fewer mishandled bags and denied boardings, the report found that complaints to Transportation climbed as much as 400 percent over 2019.

Refund-related grievances made up about 83 percent of all complaints last year, which pushed Odeon’s overall quality rating scores for most airlines studied.

Southwest had the lowest consumer complaint rate of all the airlines rated with 2.64 complaints per 100,000 passengers.

Frontier Airlines, which came in last place in the rankings, had the highest consumer complaint rate with 49.30 complaints per 100,000 passengers.

The airline industry faced record lows for travelers in 2020 due to travel restrictions resulting from the pandemic.

The Centers for Disease Control and Prevention (CDC) said in early April that people fully vaccinated for COVID-19 can safely travel domestically.

More than 1.6 million people traveled through airports Sunday, the first time travel had been this high since the pandemic began.