When it comes time to trade in your frequent-flier reward points for seats on an airplane, low-cost airlines do the best job of getting you in the air.
That was the conclusion of a study released this month by IdeaWorks, a Wisconsin consultant to the airline industry. In March, IdeaWorks submitted nearly 7,000 booking requests through the frequent-flier websites of 23 airlines. Seats were requested for the airline's most popular routes in June through October.
The study had a 93.5 percent success rate of finding available seats on low-cost airlines around the world, including U.S. carriers such as Southwest Airlines, AirTran Airways and JetBlue Airways. In contrast, the study had a 62.9 percent success rate with larger carriers such as American Airlines, US Airways and Delta Air Lines.
In fact, the study found that Southwest had a 100 percent success rate for finding available seats -- tied for the best rate with budget airline Air Berlin. Among other U.S. carriers, AirTran and United Airlines each had a success rate of 87 percent, according to the study.
At the bottom of the list were American with a 45.7 percent availability rate, US Airways with 33.6 percent and Delta in last place with 27.1 percent.
Jay Sorensen, president of IdeaWorks, said he thinks larger airlines such as American and Delta have not set aside enough seats to meet the demand from frequent fliers who accumulated reward points through popular credit card programs.
"These frequent-flier programs have been on steroids with their ability to generate revenues," he said.
Over the last three years, the study found, the world's airlines improved the overall availability of seats for frequent fliers. The study found that all airlines tested in 2010 had an average score of 65.8 percent. The seat availability rate improved to 68.6 percent in 2011 and to 70.9 percent in 2012, according to the study.