(CNN) -- Virgin America ranked No. 1 in an annual airline rating report for the second consecutive year.
Overall, the U.S. airline industry had its best-ever performance in 2013 on the Airline Quality Rating, released Monday. The statistical study of U.S. airlines, co-authored by aviation and marketing professors, has been conducted since 1991.
The airline ratings are determined using a formula that considers multiple factors in consumer decision-making. On-time performance receives the most weight in the formula, followed by denied boardings, mishandled baggage and customer complaints. Data for all the criteria are drawn from the U.S. Department of Transportation's monthly Air Travel Consumer Report.
Virgin America, the top overall scorer, had a slight dip in its on-time performance in 2013 from 2012, dropping to 82.1% from 83.5%. The airline had the best record for baggage handling in 2013 among all the airlines rated.
The U.S. airline industry saw an overall improvement in 2013 over 2012, according to the study, despite declines in two of four areas considered.
"I think generally speaking for the last several years we've been in a pretty good place from a performance standpoint," said study co-author Dean Headley, an associate professor of marketing at Wichita State University. The Airline Quality Rating is conducted jointly by Headley and Brent Bowen, a professor and dean at Embry-Riddle Aeronautical University.
"As an industry we're in a good spot. People seem to be flying. Price isn't scaring them away, which seems to be what people look at most," Headley said. What doesn't always match up with performance is consumer perception of air travel, he said. The ratings don't assess airfares.
On-time performance for U.S. airlines dropped in 2013 from 2012, with 78.4% of arrivals on time in 2013, compared with 81.8% in 2012. The number of mishandled bags jumped in 2013, from 3.07 per 1,000 passengers in 2012 to 3.21 in 2013.
Hawaiian Airlines had the best on-time performance -- 93.3% -- among the 15 U.S. airlines rated, while American Eagle's 72.1% on-time arrivals put it at the bottom of the pack.
Industry performance improved in two of the four areas considered, with fewer denied boardings and customer complaints in 2013 than 2012.
Southwest Airlines had the lowest consumer complaint rate of all airlines -- 0.34 per 100,000 passengers. Southwest routinely has the fewest customer complaints among U.S. airlines. Frontier had the highest rate of customer complaints, with 3.09 per 100,000 passengers.
The industry is definitely in a period of readjustment, Headley said. United-Continental is still ironing out its merger, and the Southwest-AirTran and American-US Airways mergers still have a way to go. Things are bound to change for consumers, he said.
"I would stay flexible, as always. When you're traveling by air, you may have your favorite carrier, routes and times, but stay flexible. Everything's on the block at some point."
Here are the rankings of the U.S. carriers evaluated by the rating:
1. Virgin America
6. Endeavor Air
7. US Airways
15. American Eagle