Trying to use your miles? Well, get in line

David Borak, an environmental policy analyst from Washington, D.C., has 300,000 frequent-flier miles with United, but for five months now, he hasn't been able to use them for a family vacation in Rome next summer. While his dates are flexible, he said there were no seats available for the so-called Saver price of 50,000 miles.

Exasperated, he posted a message on FlyerTalk.com, a Web site where travelers share tips about getting the most out of loyalty programs, venting his frustration: "I could not even find one lousy award ticket (economy or business) for IAD-FCO for the next 12 months!" he wrote, using the airport codes for Washington's Dulles and Rome's Leonardo da Vinci airports. "What gives?"

There are similar gripes about nearly every frequent-flier program. "I've been looking for standard coach seats IAH-HNL for the 1st week of August since last October," a Continental OnePass member recently posted, referring to the airports in Houston and Honolulu. "No luck whatsoever." A Southwest Rapid Rewards member who couldn't find any award seats from Virginia to Denver, asked in a post last December, "Is this a trend?"

In a word, yes. Travelers have long complained about the difficulty of booking frequent-flier tickets, but now it's becoming even harder.

Fewer seats, more miles

One issue is the airline load factor. Seats filled with paying passengers averaged 80 percent in the year ended October, up 1 percentage point from 2006. The industry considers that level a near-capacity load factor, and as a result, airlines have less incentive to offer award seats on planes they can easily fill with paying passengers.

Meanwhile, airlines are issuing miles on credit-card payments for everything from groceries to rent, resulting in a glut of miles competing for a shrinking number of seats. And airlines have been tweaking their frequent-flier programs, making miles both harder to redeem and cheaper in value.

On Feb. 1, Continental upped the number of miles required for some of its so-called EasyPass awards, raising the price of a first-class domestic flight to 100,000 miles from 90,000, and the price of the so-called SaverPass award to 50,000 from 45,000. And Delta did away with a key selling point of its premium SkyChoice awards (which cost twice as much, 50,000 miles for a domestic ticket, as its basic SkySaver award): a guarantee of an award ticket as long as there is an open seat on the plane.

Tim Winship, editor at large for SmarterTravel.com and the publisher of FrequentFlier.com, said, "It's been this incremental process whereby they raise a little here, they raise a little there, they cut back on the availability of restricted awards, which has the effect of forcing people to redeem twice as many miles."

New expiration dates

And if award-ticket inflation weren't enough, many airlines have also imposed shorter expiration dates. American, United and US Airways have 18-month expiration policies, and Delta has cut the life span of its SkyMiles from three years to two. The latest to cut back is Alaska Airlines. Effective April 1, it will wipe the miles from any account that has been idle for two years.

The airlines say they give away plenty of award seats each year. In fact, they say, more frequent-flier tickets are being awarded than ever: American Airlines issued 4.8 million AAdvantage award tickets and upgrades last year, up about 85 percent from 2006. And Continental issued 1.84 million OnePass award tickets and upgrades last year, up 7.6 percent from the previous year. Those numbers, however, don't reflect how many customers tried to use their miles and failed.

Beyond obsessively checking for new award seats, there's unfortunately little that mileage members can do to improve their chances. One strategy is to search for flights with less demand, like off-season destinations. Award tickets to Europe, for example, are still available if you travel before the summer high season.

Be sure to check for award seats on partner airlines. Some airlines are starting to make it easier to do so online. Delta's Web site now lets you search for award tickets for SkyTeam alliance partners, including Continental and Northwest.

And don't hesitate to pick up the phone and call the airline directly, recommended Randy Petersen, editor of InsideFlyer magazine. While most airlines charge fees for making award reservations by phone, a booking agent can often pull together an award itinerary using partner airlines.

Check out the online forums of FlyerTalk.com, FrequentFlier.com and FlightBliss.com, where mile-obsessed travelers share their strategies for earning and redeeming miles.

Some airlines, including American and US Airways, also point out routes on their Web sites that have good award availability at a given time of year.

And keep checking. Airlines typically load seat inventory 330 days in advance but can release award seats at any time based on cancellations, changes or demand levels.