( CNN ) Think it 's hard to redeem your miles for an airline award ticket ? It depends on which airline rewards program you 've chosen , which route you 're flying and when you book your ticket , according to a new Consumer Reports study of 70 million passenger trips over the past two years . The magazine collected statistics comparing award-seat availability for the five biggest U.S. airlines on domestic routes . The top performer was Southwest Airlines , which offered the most award tickets , 11.9 million , and the highest percentage of award tickets -- 11.5 % of 103.1 million total passenger seats . `` The high number of award tickets is directly related to Southwest 's unique combination of 'Every Seat is an Award Seat , ' no blackout dates , points that do n't expire , and a route map that reaches more than 90 different destinations in the U.S. and beyond , making us the largest domestic carrier in the U.S. , '' Southwest spokesperson Thais Conway Hanson told CNN . `` Unlike other carriers , we also do n't charge fees for close-in bookings or penalize you for canceling your trip if something else comes up . '' At the bottom of the list was JetBlue , which offered the lowest percentage of award seats and the fewest number of award tickets of the five biggest U.S. airlines : 892,000 one-way passenger tickets , or 4.5 % of its total 19.7 million U.S. seats . ( JetBlue only operates in 10 of the top 25 markets included in the study . ) Many JetBlue customers fly the airline only once or twice per year , making it hard to accumulate miles , an airline spokesman told the magazine . By not allowing miles to expire anymore , the airline says customers will be able to eventually redeem them . Delta Air Lines came in second place with 5.6 million U.S. award seats ; United Airlines ranked third with 5 million U.S. award tickets ; and American Airlines was fourth with 3.5 million U.S. award seats . What are the world 's safest airlines ? Remember that award tickets are n't actually free . The cost of miles is built into everything you buy that 's earning you miles , and the airlines profit from you not using your miles at all . So it behooves consumers to book award travel carefully . On average , nearly 10 % of passengers on the five airlines analyzed by Consumer Reports flew on domestic award tickets , but some of them were n't getting the best value for their miles . While many U.S. fliers redeemed miles on American Airlines flights from Los Angeles to San Francisco , the cheapest average fare on that route was just over $ 100 -- not worth the 12,500 to 30,000 miles needed for an award ticket , Consumer Reports says . Better to use them on American Airlines ' route between New York and San Francisco or Delta 's route between Chicago and Los Angeles , which are generally more expensive than that Los Angeles-San Francisco route , according to Consumer Reports ' calculations . While award-seat availability is important , it may not matter as much as passengers ' overall satisfaction with an airline . Southwest had the highest customer satisfaction score ( 86 ) , followed by JetBlue ( 85 ) , Delta ( 70 ) , American ( 66 ) and United ( 63 ) . And do n't forget the fees . Southwest does n't charge any fees , while other airlines tack on fees for checking bags , booking by phone , changing plans and more .
Southwest Airlines tops Consumer Reports ' survey , with the most seats available . JetBlue is at the bottom of the list but ranks high in customer satisfaction .