Raburn looks through the cockpit window toward the arched roof of an old TWA hangar that is now the main factory for his company, Eclipse Aviation. Inside, the 1960s interior has been given a 21st-century makeover. Technicians clad in navy-blue coveralls crawl over the sleek skeletons of Eclipse 500s being readied for flight. Tangled wires dangle like entrails from the disemboweled fuselages. Though the assembly floor hums with activity, the normal cacophony of industry—hammering and welding—is eerily absent. Taking a cue from PC-maker Dell, Eclipse doesn’t manufacture anything: Parts are flown in from 85 suppliers around the world and assembled like life-size Lego models, using a technique known as friction stir welding, which requires no rivets. Raburn says Eclipse could get a jet from the factory to the runway in only four and a half days. Conventional aircraft construction takes three months. But so far, Eclipse has needed 30 days because of manufacturing inefficiencies, supplier delays, and ongoing design changes.

The Eclipse 500 is a scant 33.7 feet long and costs $1.5 mil­lion, a bargain for a private jet. (The cheapest jet on the market now goes for $2.25 million.) It has a sensuous, conical nose, stubby wings, and a T-shaped tail flanked by two trash-can-size turbine engines. Sitting on the tarmac, it looks like a Gulfstream that has been shrunk in the dryer. Inside the cockpit, the traditional dials and gauges have been replaced with a trio of large computer screens; a videogame-like joystick takes the place of the pilot’s control wheel. The Eclipse can reach an altitude of 41,000 feet and can fly at 400 m.p.h. for three hours or so. Sitting in its leather interior is like jumping into the passenger seat of a Lexus.

Since forming Eclipse Aviation in 1998, Raburn has raised close to $1 billion in private financing from investors, including Bill Gates, biotech billionaire Alfred Mann, and UBS, the Swiss investment bank. His utopian vision of affordable jet travel has inspired nearly a dozen companies—including industry giant Cessna, Brazilian aircraft maker Embraer, and even Honda—to develop models of their own, creating an entirely new category of plane known as very light jets, or V.L.J.’s. Raburn’s acolytes see him as an aviation pioneer equal to Howard Hughes.

But Hughes’ most ambitious design ultimately flopped, and Raburn risks a similar fate. The Eclipse 500 is three years behind schedule, and it will be several years before the assembly line churns out the three planes a day that Raburn has predicted. In June, he skirted financial ruin when a deal for $200 million in financing imploded the night before it was to close, forcing him to scramble to secure new funds. “The company was nearly destroyed,” he says wanly.

Raburn’s critics—and he has many—say he is a dilettante, a pariah, a Silicon Valley refugee who naively believes airplanes can be snapped together like computers. His detractors also lampoon his public pronouncements about the Eclipse’s revolutionary potential, and they snipe over the investment bubble in mini-jets that has gripped the aviation industry. Foes derisively refer to the Eclipse as a “dotcom with wings.”

Raburn—who, at 57 years old, has a boyish face, a stocky frame, and a short temper—clearly enjoys a dogfight. Back on the ground, he says, “This industry has been screwing customers for decades, and I’ve been very disdainful of that.” He wears a golf shirt and charcoal slacks and sips coffee from a mug ringed with block letters: "I love the smell of jet fuel in the morning." He offers another explanation for his legion of enemies. “I guess I’m the world’s biggest asshole.”