Attention billionaires: the world's biggest airliner, the Airbus A380 superjumbo, has been ordered by a mysterious buyer - for private use.

The giant Airbus plane risks making the Lear Jet, which used to be the ultimate symbol of ostentatious air travel, look like a penny-pinching alternative.

The A380, which enters service later this year, is capable of carrying 840 passengers.

Airbus sales director John Leahy declined to say when or to where the jet would be delivered.

"I can't tell you who it is but he's not from Europe or the United States," Leahy said on the sidelines of the Paris Air Show.

The buyer is likely to have paid more than US$300 million for the standard plane, according to the latest Airbus catalog prices, but will then have costs for customization.

Aage Duenhaupt, spokesman for Lufthansa Technik, which converts large commercial aircraft into private jets, said most of the company's clients come from the Middle East.