On your 50th birthday (or on your 60th, 62nd, or 65th), you qualify for hundreds of special opportunities and money-saving offers that have lots of younger people wishing they were older--all for a couple of good reasons. First, as a person in your prime, you deserve them. Second, as part of the fastest-growing segment of the American population, you represent an enormous market of potential consumers, a fact that has become quite apparent to the business community. More than a quarter of the U.S. population today is over 50; by 2020 that proportion will increase to a third as the first wave of 77 million baby boomers turns 50. About 34 million Americans-1 in 8--are now over 65, and it is estimated that by 2030 this group will increase to more than twice that number. Besides, life expectancy is higher today than ever before, and most of us can expect to live a long, healthy, and active life.

But, first, keep in mind:
Rates, trips, and privileges tend to change at a moment's notice, so check out each of them before you make your plans. Airlines and car-rental agencies are particularly capricious, and it's hard to tell what they offer from one week to the next. The good deals in this article are those that are available as we go to press.
Always ask for your discount when you make your reservations or at the time of purchase, order, or check-in. If wait until you're checking out or settling your bill, it may be too late.
Also remember that discounts may apply only between certain hours, on certain days of the week, or during specific seasons of the year. Research this before making reservations and always remind the clerk of the discount when you check in or pay your fare. Be flexible when you can and travel during the hours, days, or seasons when you can get the best deals.
It's particularly important when traveling to carry identification with proof of age or membership in a senior club. In most cases, a driver's license or passport does the job. So, in some cases, does the organization's membership, a birth certificate, a resident alien card, or any other official document showing your date of birth. If you're old enough for a Medicare card or Senior ID card, use that.
Don't always spring for the senior discount without checking out other rates. Sometimes special promotional rates discounts available to anybody any age turn out to be better deals. The car-rental companies and railroads, for example, are famous for this. Ask your travel agent or the ticket seller to figure out the lowest possible available rate for you at that moment.
Some of these bargains are yours at age 50, usually but not always tied to membership in a senior organization. Others come along a little later at varying birthdays, so watch for the cutoff points. Also, in most cases, if the person purchasing the ticket or trip is the right age, the rest of the party, a traveling companion, or the people the room are entitled to the same reduced rates.

The following is a list of the Author's personal favorite travel deals:

ALASKA WILDLAND ADVENTURES
AWA's Senior Safaris are adventure tours designed specifically for energetic mature travelers who are looking for action and can move right along but don't want to worry about keeping up with 30-somethings. Several 7- and 9-day senior trips are offered in the summer months, during which AWA also has similar but more ambitious ecotours for all ages. The itinerary, planned to accommodate all levels of ability and stamina, gives you a glimpse of Alaska up close as you raft down the Kenai River; travel by yacht in Prince William Sound to watch whales, sea otters, glaciers, and birds; travel north to tour national parks and refuges; hike in forests and across the tundra; visit historic bushtowns; and view grizzly bears, moose, and other wild creatures.

Among other lodgings, your group stays at a comfortable motel in Kenai and the Denali Backcountry Lodge in Denali National Park, always with your own private bathroom. Mention your membership in a recognized senior organization, and you will get a $50 discount.

For information: Alaska Wildland Adventures, PO Box 389, Girdwood, AK 99587; 800-334-8730.

WARREN RIVER EXPEDITIONS
Warren River Expeditions offers whitewater raft trips for seniors down Idaho's Salmon River , the longest undammed river in the country--fast and wild in the spring, tame and gentle in late summer. You'll float through unique ecosystems, down the deep Salmon River Canyon, and through the Frank Church Wilderness Area, where you'll view the lush scenery and the abundant wildlife. Planned as soft adventure trips for people who are not enthusiastic about sleeping on the ground, the six-day senior trips put you up each night in comfortable backcountry lodges. Want to take the trip with your grandchildren? There is a grandparent expedition at least twice every summer plus a 10 percent discount for those over 50 or under 16.

For information: Warren River Expeditions, PO Box 1375, Salmon, ID 83467-1375; 800-765-0421 or 208-756-6387.

ROOTS & WINGS EXCURSIONS
Intergenerational travel is the specialty here. Among other family-oriented excursions, many trips are planned exclusively for grandparents and their grandchildren, and more just for mothers and their adult daughters. The GrandTrips include weekend adventures with other grandfamilies to such places as the Florida Keys, the Florida space coast, Amish country, and Civil War battlefields. Longer domestic journeys currently go to Hawaii, the Canadian Rockies, the Wild West, Alaska, and Chesapeake Bay Abroad, destinations include the British Isles and Italy.

Mother & Daughter Discoveries are designed to allow mothers, daughters, and grandmothers to spend time together enjoying one another's company and special places such as the wine country of California, the antebellum South, Annapolis, New York City, and Bermuda.

For information: Roots & Wings Excursions, 423 Carlisle Dr., Herndon, VA 20170; 800-722-9005 or 703-834-7244.

SCANRAIL 55+ PASS
Sold only on this side of the Atlantic, Scanrail gives you unlimited travel in Denmark, Finland, Norway, and Sweden. If you're over 55, buy the Scanrail 55+ Pass, giving you the same privileges, but for less than younger adults pay.

For information: Rail Europe, 2100 Central Ave., Boulder, CO 80301; 800-4-EURAIL (800-438-7245).

EUROSTAR:THE CHANNEL TUNNEL
Eurostar offers 12 round-trips a day through the tunnel that goes under the English Channel connecting Paris or Brussels with London. The senior fares--you're eligible if you're over 60--are about 20 percent less than the regular adult fares for first-class tickets. They are also unrestricted and refundable.

For information: Rail Europe, 800-EUROSTAR or 800-4EURAIL (800-438-7245).

BERMUDA
Every year Bermuda dedicates the month of February to visitors over 50. During Golden Rendezvous Month, there are daily special events, activities such as duplicate bridge and ballroom dancing and talks on the traditions, culture, history, and flora and fauna of the island, plus free bus tours to see the sights. Many hotels offer special packages and rates, and the Visitors Service Bureau in Hamilton distributes discount coupon books good at retail stores and attractions plus free ferry/bus tokens.

For information: Bermuda Department of Tourism, 310 Madison Ave., New York, NY 10017; 800-223-6106.

SWITZERLAND
The Swiss Hotel Association will provide, for the asking, a list of over 450 hotels that participate in the Season for Seniors, giving reduced rates to women over 62 and men over 65 (if you are a couple, only one of you must be the required minimum age). The only catch is that in most cases the lower rates do not apply during peak travel periods, including the summer months.

The Swiss Museum Passport, good for a month, gives you admission to about 180 museums for $25 if you are a woman over 62 or a man over 65. That's $5 less than it costs a younger adult. It is available at participating museums, tourist offices, and train stations in Switzerland.

For information: Switzerland Tourism, 608 Fifth Ave., New York, NY 10020; 212-757-5944.

MERRY WIDOWS DANCE CRUISES
Designed for solo women from 50 to 90 who love to dance but don't have partners, the Merry Widows Dance Tours runs many cruises every year to such places as the Caribbean, Southeast Asia, Alaska, Greece and the Mediterranean, and the Panama Canal. The trips range from 7 days to 18. Sponsored by the AAA Auto Club South, the cruises take along their own gentlemen hosts, one professional dancer for every five women. Each woman receives a dance card that rotates her partners every night throughout the cruise, whether she's a beginner or a polished dancer. The men are also rotated at the dinner tables so everyone gets the pleasure of their company. You don't have to be a widow and you don't even have to know the cha-cha or the macarena to enjoy these trips.

Merry Widows also operates tours to major resorts, in such settings as the Cloister in Georgia's Sea Islands and Sedona Spa in Arizona. Out-of-the-country resort destinations include European capitals, the Greek Isles, Turkey, Tahiti, Hawaii, and the Caribbean.

For information: Call your travel agent or contact Merry Widows Dance Tours, 1515 N. Westshore Blvd., Tampa, FL 33607; 800-374-2689.

MATURE TOURS
Mature Tours specializes in travel for "youthful spirits" over the age of 50 who wish to roam the world with other mature travelers. A division of Solo Flights, which has a long history of catering to the single voyager, it welcomes both Solo seniors and couples on its trips. Regular destinations include Costa Rica, Spain, and New York City. Also frequently on its schedule: steamboat cruises on the Mississippi River, some with add-on stays in New Orleans.

For information: Mature Tours, 10 Greenwood Lane, Westport, CT 06430; 800-266-1566 or 203-256-1235. dol.gov

From Unbelievably Good Deals and Great Adventures That You Absolutely Can't Get Unless You're Over 50 by Joan Rattner Heilman. Copyright ©1998 Joan Rattner Heilman. Excerpted by arrangement with Contemporary Books. $11.95. Availalble in local bookstores.