Consumer Reports looks at airline frequent flyer programs

NEW YORK (WABC) -- The New York-area airports are some of the busiest in the country, and more than 300 million belong to frequent-flyer programs. But with all the blackout dates and limited seats, it can be frustrating.

Consumer Reports checked out nine frequent-flyer programs and found big differences.

They asked staffers to try booking round-trip tickets using their frequent-flyer miles with Alaska, American, Delta, Frontier, Jet Blue, Southwest, Spirit, United and US Airways.

They searched for a seat on the five most popular U.S. routes for flights that departed in three days, one month and three months.

"Options were often limited," Consumer Reports' Mandy Walker said. "Our results are just a snapshot in time, but we had the most choices on Delta, followed by Southwest and US Airways."

The deals also varied widely.

"Spirit required the most miles for the routes we checked, followed by US Airways," Walker said. "And they both charged the highest booking fees, more than $100 for last-minute travel."

The best mileage deals were with Alaska Airlines, followed by JetBlue, American, and Delta.

And Consumer Reports found you are usually far better off booking early.

For example, on Southwest's Chicago to New York route, a round-trip ticket went from around 17,000 miles a month before departure to more than 77,000 for a flight three days away.

"On short notice, United was the only one that sometimes lowered the number of miles needed to book a seat," Walker said.

Whatever you do, Consumer Reports says don't hoard frequent-flyer miles. You run the risk they'll expire.