Friendly Skies

Near the top of the list of almost every billionaire's must-have list is a Gulfstream jet. The sleek, top-of-the line Gulfstream V can zip eight passengers from New York City to Tokyo at 87% of the speed of sound in a cabin that looks more like a Manhattan pied-a-terre than an airplane. At this time of year, airports in Aspen, Colo., Miami and Maui are so jammed with Gulfstreams and other jets that you'd have to call in advance to find room to park yours. The most luxe of these planes come crammed with the toys that keep billionaires happy: showers, kitchens, satellite TVs. Gulfstream in particular has always been one fetish ahead of the acquisitive billionaire.

But Gulfstream's latest option may surprise: a $3 million anti-missile system discreetly installed near the tail of the $20 million-plus jets. Originally designed for military use, the Sanders AN/ALQ-204 works by sending out signals that confuse heat-seeking missiles, causing them to make turns that yank the original target out of range. When used on larger jets such as a Boeing 747, the devices are installed on each engine so that missiles don't have a chance to establish a heat lock. The Gulfstream's rear-mounted engines require only a single unit.

So far, Gulfstream has sold six of the devices--it won't say to whom--but customers are asking for more. The system comes with an on-off switch, and a Gulfstream spokesman says it particularly should be switched on when a plane is landing--a moment when it is moving slowly and within range of portable missiles. Who knew Aspen was so dangerous?

--By Joshua Cooper Ramo