In a unique arrangement, Pan Am and Aeroflot, the Soviet airline, are jointly introducing what an Aeroflot official terms a "friendship air bridge." It is the first nonstop air service between the United States and the Soviet Union (New York-Moscow) -- with the added factor that the two airlines will share the flights. Each flight will carry both Pan Am and Aeroflot attendants to serve passengers.

Scheduled to get underway on May 15, the unusual Pan Am/Aeroflot service is the result of what Pan Am Chairman C. Edward Acker calls "the new business climate that exists in U.S. and Soviet relations." Other specialists in travel to the Soviet Union say Americans today are finding it easier to meet Soviet citizens on a person-to-person basis because of a relaxation in the tension between the two countries.

The new flights will use only Pan Am planes -- 412-passenger, wide-bodied 747s -- and they will be flown by a Pan Am cockpit crew, says Pan Am spokeswoman Pamela Hamlon. But each airline will be able to sell up to half the passenger and cargo space, charging fares at its own rates. And each flight will carry up to three Aeroflot cabin attendants, primarily to assist Soviet passengers who may not speak English.

During the summer, there will be three flights a week, departing New York on Tuesday, Friday and Saturday. Service will be reduced to two flights weekly in spring and fall and one flight weekly during the winter. The nonstop service, about eight hours and 20 minutes eastbound and eight hours and 55 minutes westbound, is expected to trim about three hours off current U.S.-Soviet air links.Pan Am already serves Moscow with narrow-bodied 727s from its hub in Frankfurt, Germany, with wide-bodied connections from Washington and other U.S. cities. Aeroflot flies from the United States with a stop at Gander in Canada. These flights will continue, and the nonstop service will supplement them.

Pan Am inaugurated U.S.-Soviet Union air service in 1968. Both Pan Am and Aeroflot flights were suspended from 1981 to 1986 during a cool period in U.S.-Soviet relations. The nonstop service was announced by Acker and Vladimir Kourkou, general manager for Aeroflot in North America.On the eve of the U.S-Soviet summit, experts in travel to the Soviet Union are urging Americans to meet Soviet citizens by venturing away -- at least briefly -- from the standard bus tours of the country's cultural treasures.

The Soviet people are "very friendly and very inquisitive -- they're not bashful," says Jonathan Chase of Travel Advisors, a downtown Washington travel agency specializing in Eastern Europe and the Soviet Union. They are apt to approach you, if you are not sealed off behind a tourist bus window.

He suggests travelers who want a quick look at the Soviet Union sign up for an escorted tour (10 days for about $1,400 per person) because they are cheaper than independent travel. But then, he says, "Skip the afternoon excursion" and do some exploring on your own. In the evening, make a reservation at a restaurant away from your hotel.

"That's the best way to see the Russian character -- at a restaurant, where they become animated and like to dance."

Sometimes, a budding capitalist will attempt to befriend you in an effort to exchange rubles for dollars at a black market rate. Definitely avoid those contacts, says Chase, but otherwise be open to friendly chats with someone who may be interested in practicing a few new words of English.

You are likely to meet the local people if you travel by train, particularly in second class. It is Chase's impression that Soviet authorities are more relaxed than they were in the past about permitting Soviet citizens to mingle with outsiders. "There are so many foreigners visiting the Soviet Union today. The anxiety and paranoia of the government have faded."

Another way to see Soviet life is to rent a car and head into the countryside. Trips as extensive as a drive from Tbilisi in Soviet Georgia north through the Caucasus Mountains to Moscow and Leningrad are possible, although generally you won't be as free to roam as you are back home. It's a trip for more adventurous travelers, who either have some knowledge of the Russian language or who are good at coping with language barriers.

With a reservation made in advance, a small Soviet car currently rents for about $20 a day for a one-week period and $15 a day for a three- or four-week period. Add to that about 20 cents a kilometer as a mileage charge and $3 a day for compulsory insurance. The dropoff charge from one city to another is about $120.

The Citizen Exchange Council of New York is a 25-year-old organization geared to people-to-people travel programs between the United States and the Soviet Union. Upcoming in February is a pair of two-week cross-country skiing outings in the parks of Moscow and Leningrad and a ski resort outside Leningrad.

The idea is to put Americans in situations where they are likely to encounter the local people, says Robert Satterfield, the council's marketing director. "The Soviets in winter ski in their city parks. It's a great way to meet them." For example, if you tumble on a trail through the birch forest, somebody probably will stop to help you up. It is an opening for at least a brief, friendly exchange.

The council was established in 1962 "to promote the kind of international understanding that is better achieved between people than between governments." It stemmed from tensions in U.S.-Soviet relations at that time.

Most of its year-round schedule of travel programs is designed for arts and educational institutions and college alumni groups, but they usually are open to the general public. The ski trips are special tours offered annually directly to the public.

Each ski trip is limited to about 30 participants. Stops on the itinerary are Moscow, the city of Suzdal outside Moscow, Leningrad, and the ski resort town of Olgino near Leningrad. Departures from New York are Feb. 13 and Feb. 20. The all-inclusive cost for lodging in first-class hotels, food and air fare (via Finnair) is $1,779 per person. Ski rental is extra, or you can tote your own. For information: Citizen Exchange Council, 18 East 41st St., New York, N.Y. 10017, 1-212-889-7960.

DOLLAR UPDATE: The U.S. dollar's decline abroad has made it something of a guessing game to determine in advance how much a trip is going to cost if you are headed for the strong currency nations of Western Europe and Japan. However, some segments of the travel industry are taking steps to put stability into the planning process.

Among them:

Trafalgar Tours: A London-based tour operator, it is guaranteeing the 1988 prices for its trips to Great Britain and Europe, provided reservations are made and paid for by Dec. 31. With the dollar in flux, "this price guarantee is an insurance that any further decline in the dollar will have no effect on ... European vacation plans for 1988," says the firm. For a copy of the tour catalogue: 1-800-854-0103 or 1-212-689-8977.

Inter-Continental Hotels: The luxury chain's three well-located hotels in Paris -- Le Grand, the Meurice and the Inter-Continental -- have reduced their rates substantially from now through March 15. The new rates include both tax and service charge.

For example, winter rates at the Inter-Continental (single or double) now are about $173 a night per room from Monday through Thursday and $135 a night on weekends. The normal rate is $225 single and $255 double a night. For reservations: 1-800-33-AGAIN.

HOTEL TAXES: Taxes on hotel stays are now at 10 percent or above in several U.S. cities, making them "a factor in budgeting a vacation," according to Consumer Reports Travel Letter, a monthly newsletter.

There's not much a traveler can do about it, says the newsletter, except to consider staying in the suburbs, which might be a little cheaper. So when totaling the estimated costs of a trip, be sure to add in 10 to 15 percent for taxes.

Among the taxes listed (rounded to the nearest percent): Atlanta, 11 percent; Boston, 10 percent; Chicago, 10 percent; Dallas, 13 percent; Denver, 12 percent; Kansas City, Mo., 10 percent; Los Angeles, 11 percent; Minneapolis, 12 percent; New Orleans, 11 percent; New York, 13 percent; St. Louis, 10 percent; San Francisco, 11 percent; Seattle, 13 percent and Washington, D.C., 10 percent.

TOUR SAFEGUARDS: A national organization representing 500 North American tour operators, who schedule escorted group tours in the United States, Canada and Mexico, is introducing a new program to protect the trip deposits of customers.

Announced last month by the National Tour Association, the organization's Consumer Protection Plan provides that should a member tour operator go bankrupt the deposits it holds are covered up to $100,000 per tour company. The plan goes into effect Jan. 1.

The bulk of the association's tour operators offer escorted bus tours. Travelers booking a tour can check to see if the operator is a member, which means their deposits will be covered to the extent of the program.

At a time when travel scams are in the news, says association president David V. Lippincott, "we want consumers to know that their deposits will be protected when they travel with an NTA tour operator member."

The association is distributing a pamphlet listing its members. For a copy, write for "A Consumer's Guide to NTA Operator Companies," P.O. Box 3071, Lexington, Ky. 40596.

REDSKINS AT SEA: Three members of the Washington Redskins football team, past and present, will serve as tour hosts on a seven-day cruise of the Caribbean in the spring. They are receiver Art Monk and veterans Mark Murphy, safety, and Brig Owens, defensive back.

Their role, according to the tour brochure, is to mingle with tour participants and hold a rap session for behind-the-scenes stories about contract talks and great moments in the history of the team.

The tour, offered by Discovery Travel Center of Chevy Chase, departs Puerto Rico May 29 aboard the Song of Norway of the Royal Caribbean Cruise Line. Ports of call are St. Maarten, Antigua, Martinique, Barbados and St. Thomas. The price, including round-trip air fare from Washington, ranges from $1,390 to $1,865 per person (double occupancy), depending on the category of cabin.

For a brochure: Discovery Travel Center, 5530 Wisconsin Ave., Chevy Chase, Md. 20815, 656-1300