2011′s best airlines for mile redemption: United, Southwest, JetBlue

Frequent flyer mile programs promise a lot — a free domestic flight for 25,000 miles roundtrip or international for 50,000 miles. But redeeming miles in 2011 at those levels can be frustrating — with inventory controls on prime seats, you’re often forced into paying double the miles advertised for a ticket. However, not airline miles programs are created equal, and IdeaWorks is back with its annual study of airline mile redemption.

For 2011 United Airlines, Continental Airlines, Southwest, and JetBlue are among the easiest U.S. airlines to redeem at low mileage levels — with reward seats available 70% or more of the time.  Delta and US Airways are among the more difficult to redeem at low levels — available less than 30% of the time, often forcing you into higher mileage rewards with their three tier systems.The chart below shows the percentage of the time 2 seats were available on the dates requested.

The study simulated what many of us try to do — book free mileage travel for two people to popular destinations. It is based upon 6,720 booking queries made  at the websites of 24 frequent flier programs during the spring of 2011. Travel dates spanned June through October 2011, with 20 top routes checked to assess reward seat availability for 2 or more passengers. Last year saw similar results, with Southwest, United, and Continental among the top, and Delta near the bottom.

Which frequent flyer program is right for you?

Minimum hassle, limited routes: Southwest RapidRewards. If you don’t plan to use your miles for international travel, and want to go to places Southwest Airlines serves, then earning miles in their program is a decent  choice. It offers great reward availability and earning points is easy with a few flights and the well regarded Southwest Airlines RapidRewards Visa. The drawback is Southwest has few international destinations and often requires you to take 2-3 flights or more to get to your destinations as it doesn’t have the big hub networks of traditional airlines.

Maximum flexibility: United MileagePlus / Continental OnePass. If you might travel internationally, or just want the most possible destinations in the U.S., you should earn miles in a major airline’s frequent flyer program. United / Continental Airlines is your best choice, offering:

1. The easiest redemption among global U.S. based carriers — with seats available over 70% of the time in the study
2. More destinations than any other U.S. airline, both with the airline itself and its network of partners
3. An easy to use website at Continental.com for searching for reward availability. There isn’t a simpler one out there for global reward travel searches.

Remember, United and Continental have merged so your miles are freely transferrable among the two, and redemption options are the same. We recommend the Continental OnePass Plus credit card to earn miles on United and Continental as it offers several extra features not found on other cards. The Chase Sapphire Preferred also lets you transfer points directly into Continental / United miles.