FARNBOROUGH, England, July 25 (Reuters) - The Concorde was a triumph of 1960s technology, Europe's answer to America's moonshots and one that has proved not much more profitable.

While the 1970s-built supersonic planes are older than most, however, engineers say they have suffered relatively little wear and tear -- partly because they are too uneconomic to get much use.

Their high speed helps keep them young, too, since the friction of supersonic flight heats up the skin and prevents corrosive water from collecting inside.

And of course no flight lasts very long, so none of the planes has many hours on the clock.

Anglo-French in its design, construction and operation, the drop-nosed delta-wing Concorde was developed by the British Aircraft Corporation and Aerospatiale, companies that are now part of BAE Systems Plc and the European Aeronautic Defence & Space Co.

Rolls-Royce Plc and Snecma -- British and French respectively -- developed its mighty Olympus powerplants from a British bomber engine.

Concorde is the only airliner that tears down the runway under the power of afterburning engines and then relentlessly climbs and accelerates until it and its wealthy passengers are boring along at twice the speed of sound.

Passengers heading west, almost always from Paris or London to New York, arrive before they departed as the aircraft overtakes the sun.

The design turned out to be wildly uneconomical, however -- for the manufacturers, if not Air France and British Airways. Only 20 were built, 14 of them going into service.

The plane consumes an ocean of fuel on every flight, requires great maintenance for its ageing systems and yet carries only 100 passengers to pay the bills.

But when the Anglo-French partners set out to develop the Concorde in the 1960s, the whole course of aviation history seemed to be about going faster and faster.

The British de Havilland Comet and the U.S. Boeing 707 had only just begun to whisk passengers at almost the speed of sound, and it seemed natural that the next step was to go supersonic.

Soviet authorities obviously thought so too. The supersonic Tupolev-144, whose droop-snoot, delta shape bore an uncanny resemblance to the Anglo-French plane and earned it the name ``Concordsky,'' made its maiden flight on December 31, 1968, ahead of its Western rival.

But the Cold War one-upmanship ended prematurely in 1973 when a Tu-144 crashed at the Paris Air Show at Le Bourget, killing 13 people. The Soviet project was quietly shelved.

In its vision of the future, Boeing had designed its 747 jumbo jet so that it could operate as a freighter after supersonic jets inevitably took over the passenger work.

It did not work out like that.

Supersonic flight generates great noise in the form of a so-called sonic boom, which eventually ruled out flight over land.

So the Concorde was largely restricted to transatlantic use, since it could not carry enough fuel for longer oceanic missions.

Even with all the development and purchase costs paid for long ago, and with the population of rich customers far greater than when the aircraft was conceived, Air France and British Airways have found little use for their Concordes.

British Airways operates just two return flights a day between London and New York, even though it has seven of the planes.

Air France, which has kept six in service, found it could justify only one daily supersonic service across the Atlantic.

Both carriers has supplemented their Concorde income with charter flights, however. The Air France plane that crashed on Tuesday had been chartered by a German tour operator.