In the pantheon of all-time favorite do-it-yourself projects, you might expect to see the redwood hot tub kit and maybe the hot-rod engine. But slap ping together an airplane? To many, that would be tantamount to building your own nuclear reactor.

Still, that's exactly what thousands of people throughout the country are doing each year in their garages, on their patios and in small hangars at community airports. It's not easy and it's not quick, but it has become for many private fliers the alternative to a general aviation aircraft market that has run nearly dry. In recent years, as a result of massive liability insurance premiums, manufacturers such as Cessna, Piper and Beech eliminated mass production of small civilian airplanes. They are just beginning to manufacture new craft since the passage of the General Aviation Revitalization Act of 1994, which stipulates that factory-built aircraft more than 18 years old are no longer subject to product-liability claims.

Still, buying a new, factory-built craft can be prohibitively expensive. And used planes still are too costly for many would-be owner-pilots.

So, many who dream of owning their own planes are building them. "There are about 17,000 amateur-built aircraft in the United States, and there are about twice that number under construction," says Ben Owen, a spokesman for the Experimental Aircraft Assn. (EAA), an advocacy group based in Oshkosh, Wis. \o7 Experimental\f7 is the technical designation the Federal Aviation Administration applies to these craft.

That epoxy and composite squid-shaped lump under the blue tarp on George Krosse's patio represents five years of on-again, off-again labor. It is the roughly finished fuselage of an experimental canard-style aircraft. Krosse, 72, a former Navy fighter pilot and retired airline pilot who says he has flown "a DC-3 to a DC-10 and everything in between," is building the plane, called a Cozy, not from a kit but from scratch, using a set of plans provided by the designer, the Co-Z Development Corp. of Mesa, Ariz.

When finished, the Cozy will look unconventional. Powered by a small 150-horsepower Lycoming pusher engine, the plane's horizontal stabilizer is near the nose, rather than the tail, and its vertical stabilizers--called winglets--are located at the tips of the swept wings (which hang from rafters in Krosse's Newport Beach garage).

"The Wright brothers wanted to do it that way," Krosse says, "and I think they had something going for them."