SINGAPORE — When Singapore Airlines’ new Airbus 380 passenger airliner rotated off the tarmac for its maiden voyage, it was with a significant new rule about passenger behavior: Passengers were to control their “primitive urges” in the suites, please.The world’s largest jumbo jet, the A380 has 50-percent more cabin area than the previous world leader, Boeing’s 747, and Singapore Airlines installed in some of that space 12 fully enclosed first-class suites, four of which have double beds. (The other eight offer single beds.) The suites are modeled on luxury yacht interiors and feature Givenchy-designed linens, fine china and crystal glassware.

In addition to the extra room, the A380’s passenger spaces are 50-percent quieter (“virtually silent” according to Five Star Alliance, a luxury travel website) and maintain a higher cabin pressure than previous jetliners, reportedly making them much cozier.

But lest passengers get too cozy, Singapore Airlines tells suite occupants right up front that hanky panky will not be tolerated.

“If couples used our double beds to engage in inappropriate activity, we would politely ask them to desist,” company representative Stephen Forshaw told the London Times. “There are things that are acceptable on an aircraft and things that aren’t, and the rules for behavior in our double beds are the same ones that apply throughout the aircraft.”

Passengers find the rule a bit bewildering.

“So they’ll sell you a double bed and give you privacy and endless champagne — and then say you can’t do what comes naturally?” one lusty 76-year-old Australian man who booked a suite with his 51-year-old wife commented to the Times. “Seems a bit strange.”

His wife added, “They seem to have done everything they can to make it romantic, short of bringing round oysters. I’d say they shouldn’t really complain, should they?”

Singapore Airlines’ A380 is the only one in service to date. It began daily routes from Singapore to Sydney Australia in October 2007. The airline plans to introduce additional A380s flying routes to London, Tokyo and San Francisco early this year.

Quantas, Air France and Emirates Airline also expect delivery of A380s, which they have said will fly various routes between Melbourne, Sydney, Los Angeles, London, Paris, Montreal and New York.