The Masses Wait for Flights; <i> You </i> Drop Into Your Club : Airports: Airline membership lounges offer comfortable seats and free coffee. Otherwise, they vary in price and perks and comparing them can be tricky.

When it comes to choosing an airline membership lounge, Randy Petersen knows what he likes--or does he?

“I don’t like United’s Red Carpet Clubs because they want to charge me for a Coke, and I like Delta, Continental and USAir because they don’t charge me for one,� says Petersen, publisher of InsideFlyer newsletter and an incessant flyer. But then again, Petersen adds, several Red Carpet Clubs have started installing ATM machines, “and I think that’s great.�

Evaluating airline clubs is tricky, and seldom attempted. Many travelers decline to spend the extra money a membership costs (usually about $150 a year), and many of those who do pay have simply enrolled with the carrier where their frequent-flyer miles are, and never get a sense of how one club compares with another.

The club lounge concept dates back to 1939, when American airlines opened one at LaGuardia Airport in New York.

Most clubs offer discounts for spouses and multiple-year memberships. Though hours vary, facilities are fairly constant: comfortable seats, faxes, photocopiers, televisions, a bar, sometimes personal computers. Coffee and tea are always free--and at Delta and Northwest clubs, so are alcoholic beverages.

Members are supposed to use clubs only on days they’re flying with the sponsoring airline, although tickets are seldom checked. Members are generally able to bring in guests, and are urged to dress for business, but standards have relaxed over the last decade. A tieless traveler in jeans scarcely gets a second look in most clubs these days.

Several airlines say they sold many long-term memberships in the weeks before club affiliations lost their federal tax-deductible status in January. But on the whole, attendants say, the fact that clubs are no longer legitimate business deductions hasn’t substantially affected membership.

Each of the seven busiest U.S.-based airlines, listed below, maintains a club at LAX. (So do 16 other U.S. and international carriers. John Wayne Airport in Orange County houses clubs for American and United airlines, but the Burbank, Long Beach, Ontario and San Diego airports are loungeless.)

Delta. Crown Room. Some 39 clubs in the U.S. and Canada. Individual fees: $150 per year, no initiation. (Frequent flyers can also exchange 30,000 miles for membership.) Alcoholic beverages, soft drinks, orange juice free. (404) 715-6615.

American Airlines. Admirals Club. Individual fees: $100 initiation, plus $150 annually, rising to $175 on Friday. Some 29 clubs in the U.S. and 13 around the world. New clubs opening this September in Mexico City and Sao Paulo, and a new emphasis on South America, because of increasing traffic there. In the U.S., many clubs added ATM machines this year. American Airlines officials described their club membership figures as “privileged information.� Free morning pastries at some sites; prices for soft drinks and orange juice vary. (800) 237-7971.

United Airlines. Red Carpet Club. Individual fees: $100 initiation. Annual fee: $175. Some 23 clubs in the U.S. and 15 around the world, most in Asia and the South Pacific, with three in Latin America and just one in Europe (London). More than 200,000 members. ATM machines added this year at five domestic sites. United will open its third club in Chicago later this year; others are in the works in Frankfurt, Rio de Janeiro and Sao Paulo. Free cappuccino and espresso added at most U.S. clubs in the last year. Morning pastries and orange juice available at some sites; soft drink prices vary. (602) 881-0500.

USAir. USAir Club. Some 26 clubs in 20 U.S. cities, all of them east of the Mississippi except the club at LAX. Individual fees: $200 for first year, $150 for each succeeding year. Soft drinks, orange juice and morning pastries free. (800) 828-8522.

Northwest Airlines. World Club. Some 16 locations in the U.S. and nine overseas: Bangkok, Hong Kong, London, Amsterdam, Manila, Tokyo, Osaka, Seoul and Taipei. Individual fees: $175 yearly, plus $50 initiation. (Initiation fee waived if travelers have paid for and flown 25,000 Northwest miles in the last year; seniors memberships available for $115 annually, with no initiation charge.) Detroit and Minneapolis clubs are being enlarged this summer. Alcoholic beverages, soft drinks, orange juice free. (800) 692-3788.

Continental. Presidents Club. Individual fees: $200 for first year, $150 for each following year. Some 15 clubs in the U.S., plus one in London and one in Paris. About 50,000-60,000 members, by a spokeswoman’s estimate. Under a program begun last year, 30-day trial memberships can be had for $30. Soft drinks, peanuts, morning juice and pastries free. (800) 322-2640.

Trans World Airlines (TWA). Ambassadors Club. Some 14 locations in the U.S. and foreign clubs in Frankfurt, London (shared with other carriers), Milan, Paris and Rome. Individual fees: $150 for first year (with a bonus credit of 5,000 miles to the bearer’s TWA Frequent Flight program) and $125 for each succeeding year. On July 1, spousal membership fees rise from $25 to $75 yearly. The carrier has tentative plans to refurbish its clubs in St. Louis and Kennedy airport in New York this fall. Coffee, orange juice and rolls are free, but soft drinks carry a price, which varies from club to club. (800) 527-1468.