Italian charter operator Air Four operates on this planet - and in a parallel universe. "We are the first aviation service in the world to operate on Second Life, the virtual universe created by Linden Lab," says ceo Mario Peralda.

Second Life is a 3D virtual world entirely created by its residents. Since opening to the public in 2003, it has grown to be "inhabited" by millions of residents from around the world. Its creators say Second Life is a vast digital continent, teeming with people, entertainment, experiences and opportunity. Residents retain the rights to their digital creations and they can buy, sell and trade with other residents. Air Four owns a virtual headquarters, complete with airport, fleet and convention centre situated on an island shaped like Sardinia but "decidedly smaller."

In real life Air Four has a fleet of around a dozen charter aircraft and a headquarters in Milan. "The Second Life move is in keeping with the Air Four brand strategy," says Mario Peralda. "Second Life isn't a game, even if it looks like one. It is a media container, a parallel evolution of the internet. It's like the internet was just a few years ago - everyone is talking about it, but few know what it could really become."

He adds: "For now it is largely an aesthetic operation, definitely a lot of fun and very useful for increasing our name recognition. But the enormous potential of Second Life allows one to foresee extremely interesting developments from the marketing and communication standpoint. Our island features a series of runways which together form the number 4, flanked by a number of buildings: air terminal, control tower, hangar, offices, conference centre."

These structures are the creations of Mattia Crespi, team leader at ISN Virtual Worlds, and his collaborators from all over the world. "Once you reach the island, it is then possible to visit all the buildings, climb aboard the aircraft, watch them take off and land."

Air Four, whose formation incorporated Eurojet Italia, offers a 24-hour "fly on demand" service, aircraft consulting, organisation of connecting flights and ground transport or helicopter transport, and it runs a Bombardier maintenance centre at Milan's Linate Airport. The fleet includes a 13 seat Global Express, an eight seat Hawker HS125-700, a seven seat Hawker 400XP, a seven seat Learjet 60, three eight seat Learjet 45s, two six seat Learjet 40s, an eight seat Learjet 31, a CJ1 and a Citation I, both five seaters, with some 20 pilots.