Richard Branson may be the first airline executive to market expensive transatlantic flights like a dirty-minded sixth-grader.

Yesterday in Amsterdam, clad in a cap and nightgown, Branson posed between the sheets of an airborne double bed he's inaugurating next year as a high-priced business-class option on lengthy Virgin Atlantic flights. But of course he couldn't leave it at that.

The long-fabled "mile-high club" has been legitimized, he said, according to the British newspaper the Guardian. Occupants of double beds would have the privacy of a separate cabin screen dividing them from the rest of the passengers.

One might think the erotic possibilities of flight had never even been contemplated, much less explored. One might think the film "Emmanuelle" had never been made. One might even think there'd never been an airline bed before, though curator Ron Davies of the National Air and Space Museum said the first one debuted aboard American Airlines on May 5, 1934. The flight in question was a 5 1/2-hour affair between Dallas and Los Angeles. Any other debuts that may have occurred during that flight, Davies said, went unrecorded.

Perhaps several generations of pilots, co-pilots, flight attendants, navigators, passengers and political campaign alumni should write Branson and inform him that he doesn't have a clue. The first member of the mile-high club was probably some 19th-century balloonist.

Davies acknowledged that Branson may in fact have the first double bed, for which Virgin Atlantic plans to charge something like $10,000 a flight. "But I had a bed in first class on Philippine Airlines a few years ago. Wonderful flight. Slept all the way to Manila. In my pajamas."

As for the mile-high club, Davies said sadly, "Alas, I'm not a member. Despite abundant opportunities. I'm almost ashamed to admit that these days."

Ron, there's still time. Flamingo Air in Cincinnati advertises the mile-high club on the Internet (flamingoair @lunken.com), urging site visitors to "Give someone special a flight they won't forget." The company's "Flying Love Boat" is a "private, curtained aircraft" that comes equipped with champagne, chocolates and "one very discreet pilot." A one-hour flight costs $199 plus applicable taxes.

Where does Branson get off with $10,000?

CAPTION: Virgin Atlantic Chairman Richard Branson, flying high.