Frequent-Flier Miles: Harder to Redeem?

· Delta Air Lines. The first four sample destinations we searched for popped up for the exact dates we selected: from BWI to Los Angeles, San Francisco, Denver and Atlanta, for a trip in early July. Our fifth choice, Cancun, was available only for double the minimum miles, and if we wanted to try for a different date, we had to start the search again. We struck out only on our sixth choice: a particular date for St. Thomas. The date we chose wasn't available even for extra miles, and we tried alternate dates a number of times before giving up.

· JetBlue. This discount carrier did very well in our tests and has an unusual feature: You have the option of using half the required points to book award travel just one way, should both ways not be available on your optimal date.

We tried three destinations for trips in July. Dulles to Las Vegas didn't pan out on our desired dates, but we got a thumbs-up when we clicked either "previous day" or "next day." We got Fort Lauderdale, Fla., immediately. When we tried for Long Beach, Calif., there were no award tickets for our desired dates, but by changing the date by one day, bingo.

· Northwest. The airline couldn't get us from Dulles to Amsterdam on partner KLM for the minimal 50,000 miles on the days we requested for departing and returning, but was willing to give us a seat for 100,000 miles. We also checked three days before and three days after our first choices, but even with that flexibility, we couldn't find a free seat for less than 100,000 miles.

So we tried Tokyo. Again, we couldn't find what the airline calls a "perk saver" ticket for the minimum 60,000 miles round trip on the dates we first chose. However, a "perk saver" seat was available on the way there for the date we chose, if we could spend extra miles for a "perk plus" seat on the way back. That means a round trip could be had on our first-choice dates for 90,000 miles.

Northwest did come through domestically: We found our first-choice dates from Dulles to Portland, Ore., for a minimal price of 25,000 miles. Alternately, for 45,000 miles, Northwest would send us first-class on its partner, Delta.

· Southwest Airlines. The standout. Southwest immediately came through with trips to all three of our test destinations: Denver, Las Vegas and Fort Myers, Fla., from BWI. We not only got seats for the exact dates we requested, but also could choose from a broad selection of departure times.

· US Airways. The airline immediately came up with tickets from Reagan National to Orlando for 25,000 miles each on the exact dates we first requested. London, though, was a different matter: We found no availability for the entire month of July, unless we were willing to pay double the miles.

· United Airlines. The Web site turned up no flights from Dulles to Seattle for the airline's "saver" mileage requirement of 25,000 miles round trip. The site checked automatically for availability two days before and two days after our desired departure date, to no avail. United did have free tickets for the exact date we checked -- if we were willing to part with 40,000 miles. We had better luck checking flights from D.C. to Calgary, Alberta, finding "saver" tickets for the exact dates we chose.

Airlines with less availability for awards do tend to have better-than-usual availability to their hub cities: The more flights to a place, the better chance for empty seats that airlines can't sell and thus are happy to give away.

Just remember that you're competing with a lot of other fliers holding miles. Here's hoping that the tips at right will take you where you want to go when you want to go -- or something close to that -- for the price of miles and taxes.