In a time of economic dyspepsia in most of the world's industrialized countries, it turns out that the promise of free-flowing champagne, caviar, truffles, lobster and Mach 2 speed still has cachet for a small group of international air travelers.

The somewhat surprising news from British Airways this summer is that the supersonic Concorde, which even its boosters acknowledge is the great white elephant of aviation, has finally made a niche for itself.

It is actually running at a modest surplus this year of about $14 million on its routes between London and the United States.

While not exactly profitable--payments to manufacturers for maintenance are still double operating revenues--the Concorde, British Airways officials find, is attracting a core of loyal, affluent passengers, about 100,000 this year out of the airline's total traffic of 16 million. Department of Industry figures show that by 1984, Concorde will be a net gainer, making a bit over a million dollars a year.

That sum is especially paltry, however, when compared to the nearly $2 billion it took to get Concorde off the ground. Moreover, it is even less likely today than it ever was that France, Britain or any other country, for that matter, will add to the 14 supersonic aircraft that British Airways and Air France now fly. The London Times reported this week that France will propose scrapping its Concordes this fall as an economy measure.

Still, the sleek, supersonic plane with the distinctive drooping nose is becoming an accepted part of the British Airways system. In line with a recent reorganization in an effort to stem the airline's massive overall deficit, Concorde has been given a division all its own with a senior pilot, Brian Walpole, as the managing director. While no one would be foolish enough to say that Concorde has turned the corner toward a future that could justify its incredibly expensive past, there is a growing sense, as one spokesman put it, that the plane will be around for its prolonged life-span of 50,000 flying hours, or roughly another 20 years.

Concorde, naturally, continues to have its critics, ranging from those who assail the effect of sonic booms on the atmosphere's ozone layer to those who feel financially strapped Britain has no business flying a plane reserved only for the rich. (A round-trip seat costs 15 percent more than a first-class ticket on a subsonic aircraft, or about $4,400). But supporters contend that getting rid of the planes now would make little sense, given that its prospects are finally looking, ever so slightly, up.

Officials say that the New York-to-London route is now up to 70 percent of load in peak business periods. The Washington route is about 50 percent, barely enough to make it profitable once the subsidy to manufacturers gets scaled back. Traffic over the past year is up about 5 percent, which is notable because most of the trends of business travel, the mainstay of Concorde, are down as a result of the recession.

Another interesting development is the emergence of a charter business for British Concordes. For about $44,000, anyone can rent a Concorde for a minimum 65-minute smoked-salmon-and-champagne flight around the Bay of Biscay. That price guarantees a profit for British Airways and for the packagers, assuming that they can sell the 97 seats.

Since the charter service began in 1980, officials say, they have scheduled about 35 flights annually. An example of coming offerings is a package consisting of a Concorde flight to Venice with a return on the recently reopened and lavish Orient Express train. No price has been set yet, but it will be, as you might expect, high.

Two things are necessary to make Concorde really worth the trouble (leaving aside the inevitable loss of momentum that a French decision to give up would represent). First, is to get new routes for existing planes. At one time, British Airways hoped to fly four separate routes--Johannesburg, Australia, Tokyo and New York, with Singapore and Bahrain stopovers. Only the transatlantic route survived political and environmental problems.

Now Nigeria is showing interest in a joint operation of Concordes to Lagos, mainly to carry oil representatives. But experienced British Airways executives know how difficult it is to translate that kind of interest into long-term reality. An effort to share Concorde with Singapore Airways collapsed almost three years ago after years of intermittent flights.

The second way for Concorde to break through to success would be to develop an engine that is fuel efficient, enabling the aircraft to cut its high-priced ticket. That would probably mean tens if not hundreds of millions of dollars in development costs, however, and the chances of it happening are negligible. It is hard enough keeping one white elephant in the air without trying to get another potential elephant aloft.