That, perhaps, is why Greenberg said the chapter that deconstructs frequent-flier programs is one of the most useful in his new book.

“It's my contention that the airlines are actually running an unregulated lottery system these days when it comes to loyalty programs,” Greenberg said. His book notes that airlines make, on average, 1.7 cents on each mile they sell, but value outstanding miles on their books at 40 cents per 1,000 miles.

“The airlines are playing a little game of extortion,” Greenberg wrote.“Since programs aren't regulated, no airline is required to provide any seat free of charge in these programs.”

Among moves he suggests for travelers who want to redeem miles for travel:

Book 320 days in advance to get first grab at the limited number of seats allocated for frequent-flier redemption.

Go to alternateairports.com to find a nearby airport where your miles might be usable.

Inquire about alternate routings and be prepared to tolerate such travel: “United told me the only way they could get me to Hawaii (using miles) was Los Angeles, to Denver to Chicago to Honolulu. (ouch!)”

Book with a mileage partner: “All the major airlines have partners. If American can't get you to Hong Kong, maybe Cathay Pacific can, or Qantas can via Sydney.”

“If all else fails – and the reservation agent tells you there are no seats on any flight, on any route, to any nearby airport on your primary airline or any partner airline – it's time to speak to a supervisor,” Greenberg said. “In almost all cases, supervisors have the discretionary power to override computer blocks and release mileage seats.”

In his book, Greenberg alerts travelers to various airlines' mileage expiration policies. He refers travelers to milemaven.com to find out how to earn bonus miles, and he sends them to insideflyer.com/tools/mileage_converter to learn how to transfer miles from one airline to another.

PERSONAL TIPS

Greenberg spouts travel tips. Many are practical and easy, such as arranging to be picked up at airport departure entrances rather than more crowded arrival entrances. Other advice may seem less practical for many leisure travelers.

For example, Greenberg advises against checking baggage: “There are only two kinds of airline bags,” he said. “Carry-on and lost.” He said he always ships his luggage to and from destinations – using Fed-Ex three-day service. He said he paid $80 to ship two bags to the Hotel del Coronado for his long weekend in San Diego. He paid that again to have bags shipped back to New York, on the day before leaving here. (He planned to use two carry-on bags – for the things he'd need after shipping everything else home.)

“It (shipping via Fed-Ex) saves me 2 ½ hours of my life (at baggage claim) every time I travel,” he said.

Greenberg said he books all of his travel by telephone.

“Call the hotel's direct line, never the 800 number,” he advised. “But don't ask for reservations. Ask for the manager on duty or the director of sales. Those are the people who know about last-minute cancellations – so you can negotiate a great rate.”

CHEAPEST AIRFARES

Surprisingly, Greenberg does not rely on the Internet to find the best airfares. Once again, the telephone is his weapon of choice: “I've memorized the toll-free numbers of all the airlines,” he boasted, rattling off a half dozen numbers to prove it.

He also knows the formulas for escaping the black hole of taped recordings that callers get when they phone toll-free numbers. Find that key at gethuman.com.

When he gets through to an airline agent, “I ask them to punch up on the computer every fare they have for a certain route,” Greenberg said.

That's when agents usually ask the dates he wants to travel, Greenberg acknowledged.

His answer to that question: “Before I tell you, tell me what you've got on the screen. Scroll to the bottom of the list. What's that fare and what do I have to do to get it?”

Greenberg said those bottom-of-the-list fares are usually the lowest available anywhere. “You may have to travel on a Wednesday at midnight wearing snow shoes,” he said. “If that doesn't work for you, work your way up the list until you find something you can live with.”

Greenberg said once he finds the fare he wants, he asks the agent to hold it for him. “I get the PNR (booking number) – and then have 24 hours to find something better or buy the fare. That's when I go to the Web.”

Greenberg said he searches Kayak, Onetime and Travelocity to compare fares. Even with the $10 to $20 fee most airlines charge for booking by phone, the airline agent's fare is “almost always” the cheapest, he said: “As long as I'm saving a dollar, it's worth it.”

TAKE PRECAUTIONS

More tips:

Before driving off in a rental car, take photos of any dings on the car. When you return the car, be sure to check any refueling fee. “At Dollar in Hawaii, they charged me for 4 gallons more than the Geo Metro's tank holds,” Greenberg said.

Before booking a hotel, check for an infestation alert at bedbugregistry.com.

Invest in medical evacuation insurance. “I pay for it every year – even though happily I've never had to use it,” Greenberg said. “But before you buy, be sure to read the small print. On my policy (with MedjetAssist) they'll send a medically equipped and staffed jet to fly me to the doctor and medical facility of my choice. This is crucial. Many other companies will send you to the medical facility of their choice. Do you really want to be treated at a lowest-bidder HMO in Rwanda?”

(MedjetAssist requires that patients be stabilized at a medical facility before transport. Annual premiums cost $225 for individuals, $350 for families. medjetassist.com, 800-527-7478.)

 Got a tip? A favorite inn or getaway? We'll share your scoop with readers. Send your tips to alison.darosa@uniontrib.com or mail to Latitudes and Attitude, P.O. Box 120191, San Diego, CA 92112. Please include prices, Web sites, addresses and phone numbers for the places you write about. And be sure to include your own daytime phone number. Alison DaRosa can be reached at (619) 293-2036.