Age before beauty.

Airlines have taken the cliche to heart. They offer discounts to senior citizens that the rest of us can't get. The deals range from discounts on fares to booklets that contain flight coupons redeemable for tickets. The booklets sell for a set price and are usually valid for one year.Some airlines sweeten their senior citizen deals by allowing a companion of any age to tag along for the same discounted fare.

Also, the airlines we spoke to offer seniors a flat 10 percent discount off most published fares. When you make the reservation, tell your travel agent that you're a senior citizen. When you check in for your flight, the airline agent will double check your eligibility for the discount when you present your photo ID.

A few of the airlines have what amount to travel clubs. For a fee, you're eligible for a variety of special fares, not only on airlines but on vacation packages or even cruises.

A word from the wise: senior deals are often restricted, or they may be subject to availability. Read the fine print.

Airlines don't agree on the magical age at which you turn into a senior citizen. For most of them, it's 62. The minimum age for Unit-ed's Silver Wings Plus program is 55. To be eligible for Southwest's senior fares, you must be at least 65.

Details follow for American, America West, Continental, South-west and United. We'll cover Delta, Frontier, Northwest and TWA next week.

American offers senior citizens three different options for dis-counts.

- Ten percent discounts to passengers who are 62 years old or older.

- Coupon booklets for people who are 62 or older. Each booklet, which costs $596, has four one-way coupons good for travel within the continental United States. A ticket to Hawaii takes two coupons each way.

- The AActive American Travel Club, for people who are 62 or older, is accepting memberships for a limited time. The club offers bargain airfares for both domestic and international destinations. It also offers a "companion option" that allows the senior citizen to bring along a companion of any age for the discounted fare. The club has a special toll-free phone number through which members handle their transactions. The annual fee is $40 for an individual member and $70 for a membership with the companion option. Fares valid through Sept. 30, 1999, are based on zone pricing and require at least a 14-day advance purchase. Round-trip fares effective Oct. 1, 1998, start as low as $98 for domestic travel Mondays through Thursdays, with an additional $20 charge each way for travel on Friday, Saturday and Sunday. Seating is limited and restrictions apply. Memberships are nonrefundable and nontransferrable. Membership benefits are effective beginning Oct. 1, 1998, and are valid through Sept. 30, 1999. A bonus: New members will be able to use the program's current benefits as soon as they enroll. Beginning Oct. 1, the club will offer other goodies including zone fares to Japan, discounts on American Airlines Vacations tours, Alamo Rent A Car and the AAdvantage Golf for Miles program and double miles with each stay at Radisson Hotels. For information or to enroll, call 800-421-5600.

America West has two senior citizen discount programs.

- People who are 62 or older are eligible for a 10 percent discount off any published fare.

- The airline's Senior Saver Pack coupon book has four one-way coupons that are good for coach travel on any America West operated flight in the lower 48 states and to Vancouver, B.C. It sells for $548. You may transfer coupons to a maximum of two children between the ages of two and 12 when accompanied by a Senior Saver Pack holder. Seats are limited and may not be available on all flights. Coupons are valid for one year from the date the pack is issued. The pack includes coupons for discounts on America West Vacations land packages and car rentals. For information or to purchase a pack, call 800-235-9292.

Continental offers a 10 percent discount on most of its fares to people who are 62 or older.

- The Freedom Passport program allows for extensive travel for one price for a limited time period for people who are 62 or older. The passports are available for four or 12 months. Purchase them for domestic or international travel, for coach class or first class. One one-way trip may be made per week using the passport, and travel to the same city is limited to three trips. Other restrictions also apply. Examples of prices: $999 for a four-month domestic coach passport; $1,999 for a 12-month domestic coach passport; $3,499 for a 12-month domestic first class passport. A friend or family member who does not meet the age requirement may purchase a companion Freedom Passport, but he must travel with the primary passport passenger. For information call 800-441-1135.

- Freedom Trips are for senior citizens who plan a few flights a year. Freedom Trip coupons may be purchased in books of four ($579) or eight ($1,079). One certificate is valid for a one-way trip in the continental United States, Canada, Mexico and the Caribbean. Two certificates are required for each one-way ticket to/from Alaska or Hawaii. Restrictions apply.

Southwest offers discounted senior fares to people who are 65 or older. The size of the discount varies depending on the destination. "There's no steadfast rule on what that fare is but it's a significant discount off the unrestricted fare," said spokeswoman Beth Harbin. To get an idea, we called Southwest's reservations number and asked what the senior fare from Salt Lake City to Oakland, Calif., was, leaving June 23 and returning June 26. It was $64 each way, compared to an unrestricted fare of $117 each way.

United offers a 10 percent discount off any published fare to people 62 or older.

- The airline's Silver Wings Plus program is available for two different time frames: two years and lifetime. The two-year membership costs $75. The lifetime membership costs $225. You're eligible if you're 55 or older. For information or to request a membership acceptance application form, call, 800-720-1765 (Monday thru Friday 8 a.m. to 6 p.m. central time), or consult the Web at (www.silverwingsplus.com).

The membership acceptance application has the details and restrictions may apply. You'll have to do your homework to figure out what you stand to get for your money.

Here are a few of the benefits we could ferret out: When you join, you're eligible for "welcome gifts." Welcome gifts for two-year members include three $25 travel certificates from United; one $50 savings certificate from Air Canada and one $100 savings certificate from Lufthansa (Germany's flagship carrier). Welcome gifts for lifetime members include three $50 certificates from United, two $50 savings certificates from Air Canada, two $100 savings certificates from Lufthansa and two $125 savings certificates from SAS (the Scandinavian carrier). Welcome gifts for both two-year and lifetime members include 50 percent off regular room rates at participating ITT Sheraton, Hilton and Pan Pacific hotels and resorts.

Ongoing benefits include special savings to select domestic and international destinations; and 50 percent savings at participating Westin Hotels such as the Peach-tree Plaza in Atlanta, Copley Place in Boston, Mission Hills Resorts in Palm Springs, the Swan Hotel at Walt Disney World and the Westin Maui.