For anyone wanting to earn reward miles on their favorite airline, the options are many. Your credit and debit cards can earn miles, so can taking online surveys or taking part in experimental drug trials (okay, not that last one). But while it’s becoming increasingly easy to accrue miles, it’s becoming more difficult to actually cash them in.

When the economy went the way of the Tidy Bowl Man in 2008, airlines saw a spike in the number of travelers redeeming miles for free seats and upgrades.

But as the airline reacted to the economic downturn by reducing the number of flights, meaning more paying passengers on fuller planes — and fewer seats for reward travel.

“There are too many people earning more miles chasing fewer seats,” George Hobica, founder of Airfarewatchdog told the Houston Chronicle.

A recent survey attempted to book two reward travel seats on 22 airlines for travel to each carrier’s largest markets between June and October and the results varied wildly.

At the top of the list was Southwest, for which the survey had a 99.3% success rate.

All the way at the bottom was U.S. Airways, which only yielded a successful booking 10.7% of the time.

Currently the country’s largest airline, Delta, didn’t fare much better, with only a 12.9% success rate.

Okay, so you’ve managed to book a seat. But if you’re booking anytime close to the date of departure, there’s a chance you could be hit with some hefty last-minute booking fees.

American Airlines charges up to $100 for booking within three weeks of departure. Continental charges up to $75 for bookings within 21 days of departure, but their betrothed airline United recently killed its last-minute fee, so it remains to be seen which policy will win out in the end.

Piles of miles grow tougher to spend [Houston Chronicle]

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