Late last month, three young Air Force pilots set off on a commercial flight from Baltimore to Frankfurt for a week of spending -- and profit-making.

Taking advantage of the strong dollar, they became amateur "gray-marketeers." They bought three 1980 Mercedes-Benz and BMW convertibles for $13,500 each, plus $3,000 apiece for duties, freight and conversion of the cars to U.S. safety and emissions standards.

Back in this country, their Washington-area customers had paid them $21,000 in cash per car, giving them a tidy $4,500 profit while still saving the buyers $8,000 to $9,000 each off the price of similar autos purchased here.

"The strong dollar has made the savings really incredible," explained one pilot, who asked not to be named. "When you get over there, you really should do yourself a favor and get one, too."

At Harrods, the stately London department store that caters to the royal family, the stakes were lower, but the goal for American shoppers has been much the same.

In the third-floor china and crystal department, customers from the United States circle the displays, calculators in hand, converting pounds to dollars and subtracting value-added taxes to determine the number of place settings they can afford. The reason for the crowds: The cost of buying the goods in London with dollars is only one-third to one-quarter of the price for the same items bought in the United States.

The sharp rise of the dollar against major currencies, including the West German deutsche mark, the British pound, the French franc and the Italian lira, has turned Europe into a vast shopping mall for an increasing number of Americans. According to the European Travel Commission, 6 million Americans will visit Europe this year, up from a record 5.5 million in 1984 and 4.8 million in 1983. And they will consume at a record rate -- an estimated $5 billion, including air fare, compared with $4 billion in 1983.

Prices of many goods imported from Europe have always been cheaper there than in the United States, but the strength of the dollar makes them seem more like bargains than ever, retailers say. Analysts say Americans abroad are spending with a frenzy fueled by the belief that never again will they be able to buy so much for so little.

And while no definitive figures exist yet to document the effect this shopping spree is having on the fortunes of stores in the United States that sell imported goods, many retailers here -- particularly urban stores dealing in expensive luxury goods -- clearly are worried.

Some are dropping prices slightly, but others, unable or unwilling to pass savings onto customers here, are acting to protect their sales and profits. They are mounting lobbying efforts in Congress and refusing to allow phone and mail orders at their stores in Europe.

"We are not overjoyed because of our American operations," admitted Richard Cohen, director of Burberry's wholesale operations at its six U.S. branches. "We are not setting the world on fire."

"It certainly has affected our business," said Val Cook, vice president of Saks Jandel Inc., the Washington retailer that caters to well-heeled women dressed by Yves Saint Laurent, Chanel, Lagerfeld, Gucci and other top European designers. "It have been worrisome to everyone, to all the retailers."

The pound -- selling for about $2.38 exactly 10 years ago and about $1.76 in April 1982 -- is now worth about $1.20 (at Thursday's close), up from $1.06 only a month ago. The mark is now worth 31.6 cents, or 25 percent less that the 41.5 cents it was trading at three years ago. Three years ago, one dollar bought barely 6.2 francs; now it buys nearly 10. The dollar purchased 1323.5 lira in April 1982; on Thursday it purchased 2010.

And while politicians and economists earlier this year debated the likelihood of "parity" -- the point at which the U.S. and British currencies would trade one for one -- parity, in fact, already has been effectively reached and surpassed, thanks to the value-added tax (VAT) that Britain assesses on purchases of goods and services. The tax is reimbursable for foreigners who take goods from the country.

When the pound was trading at $1.06, the effective rate to Americans, excluding the VAT, was a heady 90.1 cents. And though the pound had edged back up to $1.20 by Thursday, U.S. consumers were paying only $1.02 per pound for goods they were exporting.

Those figures translate into astonishingly low prices, by American standards, for goods purchased in the countries of manufacture, and the European Travel Commssion reports that Britain has been the big winner in the current American travel boom.

At Chinacraft, a chain of 35 stores across Britain, a five-piece place setting of Coalport's popular "Blue Oak" bone china was 60 for export, or about $72, compared with $275 here. A sterling silver picture frame, 21.25 before VAT, or about $25.50, was $75 here.

At Burberry's posh London store, gabardine trench coats for both men and women were fully half the price at the company's new Connecticut Avenue store -- enough of a savings, in some cases, to pay for the coat and air fare to London, too.

The difference in price of many domestic goods in French and Italian shops also is vast. Clothing by Saint Laurent and many other designers is approximately half the price charged in exclusive U.S. boutiques. Prices on crystal and china are so attractive that visitors to Paris report that Lalique customers are allowed to enter the shop only a few at a time, and a limit has been placed on the number of items each may buy. At Baccarat, customers often must wait eight to 10 months to have their orders filled.

French and Italian goods are favorably priced even in British stores, and vice versa, thanks to low tariff and freight rates for European Community members. Giorgio Armani's new longer length women's jacket and skirt was 595, or $606.90 excluding VAT, at the designer's London boutique, compared with more than $1,100 in New York; and Bally of Switzerland spectator pumps, $160 in the company's new Washington store, were $80.58 in London excluding VAT.

For the most part, the price benefits made possible by the strong dollar have not yet been passed along to consumers in the United States. Many retailers here say they buy from their European manufacturers six months to one year in advance, and are locked into prices charged at that time. Others blame exorbitant freight and duty costs.

Monroe H. Greenstein, a retail analyst with Bear, Stearns & Co., had another explanation. "Retailers here don't go to all the trouble to buy overseas to pass on the reduced price to the consumer," he said. "They go overseas to make money -- to maximize their profits. If they don't have to drop the prices of their imported goods, why should they?"

Observers disagree whether the strength of the dollar -- and what it will buy -- has alone been enough to lure Americans abroad, although Harrods tried aggressively in December by advertising its annual winter sale in U.S. newspapers.

"The Garfinkel's customer, the customer for the high-ticket items, has always traveled to Europe a lot. They have always been mobile. I don't see really that much of a change there," said Mary Lou Seckinger, public relations director for the Washington-based chain.

"We have not seen that trend at all to go abroad to shop ," agreed John Murphy, vice president for marketing for the National Retail Merchants Association in New York.

"An awful lot of people do" go abroad primarily to shop, countered Val Cook of Saks Jandel Inc.

But most people agree that once Americans arrive in Europe -- whether for business or pleasure -- they spend with abandon.

"There is no doubt that people flocking there are flocking into our stores there," said Burberry's Cohen. "When I was in London last week, I could have been anywhere in the U.S., there were so many Americans. . . ."

"They are spending like money is going out of style," said Greta Usher, manager of the Chinacraft store on Brompton Road opposite Harrods. "Our American customers have always spent liberally, but this year they are buying in a very large scale, 12 to 14 place settings with all the extra pieces."

Specialty stores here selling expensive wares are suffering more than department stores with a range of goods, analysts say. Part of the reason is because Americans are increasing their phone and mail purchases from abroad once they return, many retailers report.

"We're finding that we are getting many calls from people just back from London," Chinacraft's Usher said. "They have a chance to compare the prices, and they have second thoughts about the things they didn't buy while they were here."

Emily Cohen, manager of the Liberty's Georgetown Park branch, says that a number of customers have come back to Washington, been astonished at the difference in prices, and asked her to provide them the mail-order number for the London store.

"I say, 'By all means, pick up the phone and call them, " she said. "We are all one company. I'm hurting my own store. On the other hand, it's good for customer relations, and they'll remember it when the dollar comes down and the difference isn't so vast."

Other retailers are not so helpful. "Burberry's in London will not take orders over the phone," said Cohen in the firm's New York headquarters. "We have our own retail operations here to protect.

"What we sell you is not just a raincoat," Cohen said. "It's a lot of money, and we want to show you why it's a lot of money. We want to romance our product. You can't do that over the phone."

Many European retailers, including Liberty, Burberry and a number of china and crystal manufacturers, are beginning to lower prices here. "We have to," Burberry's Cohen said bluntly. Suzanne Urban, a representative for Chanel in New York, says that U.S. prices are only 10 to 15 percent higher than in Paris, "and that difference is solely the result of shipping and duty."

But Sak Jandel's Cook said that some her suppliers, including Yves Saint Laurent and Chanel, have raised the prices in their European shops to take advantage of the influx of U.S. customers.

In some cases where the dollar's strength has contributed to the rise of a bustling gray market, such as in the demand for German-made autos, firms have mounted efforts aimed at slowing the trend.

According to U.S. Customs figures, 36,000 cars were imported on the gray market last year. Of those, 24,000 were Mercedes, a number equal to 30 percent of the 79,000 new Mercedes sold here by authorized dealers. As a result, Mercedes Benz of North America Inc. is lobbying state legislatures and on Capitol Hill to get tighter regulations that would help clamp down on the gray market in luxury automobiles.

The cars are supposed to be converted before leaving Europe to meet strict U.S. safety and emissions control standards. But Arnold Shuman, manager of public relations for Mercedes Benz's U.S. operations, says that the conversions often aren't made or are inadequate. Furthermore, he notes, other loopholes and lax controls mean that customers can't get their gray-market cars properly serviced, and previous title and ownership often can't be traced.

Shuman said his company's lobbying efforts to retrict gray-marketeering are designed more "to protect the reputation of the name here." He calls it "disturbing" that the gray market also may be shaving profits from authorized dealers.

He adds, however, that the degree of the problem is traceable directly to the strength of the dollar. "People in the gray market have told me, when the dollar/mark level passes a certain point, it will no longer be possible for them to do it."