A California company has updated the trusty old-fashioned jetpack.

This futuristic way of getting around, made famous by the '70s kiddie show "Ark II" and the 1991 Disney movie "The Rocketeer," has actually been around for 50-odd years. A precursor was even developed by the Germans during World War II.

But it's always had one big problem: There's only so much rocket fuel a man can carry strapped to his back, and that amount tends to run out pretty quickly — in about 30 to 40 seconds.

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Now Thunderbolt Aerosystems of San Jose has doubled that flying time.

By mixing in a little kerosene with the standard hydrogen peroxide fuel, it's managed to extend air time to a whopping 75 seconds.

That may not sound like much, but it'll get a 160-pound man some 3,500 feet down the road.

The company's TP-R2G2 model will be available to the public in August for $98,000.

Thunderbolt touts the jetpack's usefulness to firefighters and rescue teams. Given the short flying time, however, it's perhaps best suited to draw attention at public events.

"You will be undoubtedly the topic of discussion after a rocket-powered human helps carry your message through the air," the Web site states.

Judging by the company's video of a test flight, featuring the very same pilot who was Sean Connery's stunt double in "Thunderball," we'd have to agree.

• Click here for the Thunderbolt Aerosystems press release, and here for more photos of the ThunderPack in action.