SOUTH BEND, IND., JULY 4 -- It doesn't get much more American than this.

Just outside the stadium where Knute Rockne coached his last season, an Independence Day parade was making its way through the Notre Dame campus in the 95 degree heat. A crowd of 4,000 spectators sat in lawn chairs or sprawled out on picnic blankets along the way. There were beauty queens and dignitaries in funny hats. There were Studebakers, T-Birds, Mustangs and Model T's. There was a kazoo band and an antique fire engine with sirens blaring at full throttle. There was a horse and buggy and a troika of Boy Scouts carrying flags while a marching band played John Philip Sousa.

And then came the familiar silver bubble, a teardrop from Americana, looking like a spaceship in the shimmering Midwestern heat. The bubble crept down Juniper Road and headed toward the famed "Touchdown Jesus," the 14-story mural on the side of the Hesburgh Library that directly faces the stadium and seems to depict Christ raising His arms to signal yet another touchdown for the Irish. And on the side of the bubble, spanning the full length of its fuselage, a sign proclaimed: "AIRSTREAMING IS A WAY OF LIFE."

Beyond the procession, over on the vast athletic fields that ring the south end of the campus, 3,300 Airstream trailers sat in meticulous rows, each one with a state flag and a Stars and Stripes flapping in the breeze. It was the 33rd International Rally of the Wally Byam Caravan Club, America's premier RV society, named after the founder of Airstream Co., maker of arguably the best and certainly the priciest travel trailer in the world.

The Wally Byam Caravan Club International (WBCCI) is a social club of Airstream owners who pick a different site every Fourth of July to hold a gathering of the tribe. Last year it was Bozeman, Mont. Next year it's Duluth, Minn. But this year's rally was in South Bend, home of the Gipper, in the heartland of America. The Airstreamers have come here to toss horseshoes and go on metal detecting excursions. They've come to elect international officers and sit in on RV maintenance seminars to learn about the latest in tow hookups and septic tank chemicals. They perform skits and go bass fishing in nearby lakes. A subgroup of widowed or singled Airstreamers calling themselves "The Freewheelers" meets for happy hours and bridge socials. A Teen Queen was crowned earlier in the week, and tonight there is a concert by "King of the Road" crooner Roger Miller. And Thursday, as the powwow draws to a close, the Airstreamers will break off into caravans and fan out across the nation, "rally hopping" their way home.

If they have a home, that is.

For many Airstreamers, of course, the trailer is the home, and caravaning is a permanent state of mind. "We don't get tired of traveling, because we go home every night," says Mary Tinga, a "dyed in the wool" Airstreamer and WBBCI officer from Castle Hayne, N.C., who lives on the road with her husband, Eelco, seven months out of the year. "There's a little saying that goes, 'We have a cottage in the mountains, and a cottage at the shore, and a cottage in many places we've never seen before.' See, that's our cottage out there, and we just put it wherever we want it."

For the past week, the sprawling campus of Notre Dame, famous for its giant golden-domed administration building, has been a sea of metallic silver. The Airstreamers have built their own self-contained city here. They've set up their own post office, with a special Zip code -- 46556. They have their own news program, which airs five times a day on Citizens Band Channel 14, known here as "Wally Byam Control." They've laid five miles of water hose and four miles of electrical wire. A fleet of red Honda mopeds has served as the Wally Byam Scooter Patrol, delivering emergency messages all over the Silver City. There is a committee to oversee every phase and fact of life here: A lost and found committee, a bird-watching committee, a macrame committee, a gem and mineral show committee, even a pancake committee. But the most prestigious of these is, by all accounts, the Sanitation Committee, charged with the unsavory task of pumping the "black water" out of every Airstream trailer here twice a week. A quirky kind of esprit de corps has developed among the sanitation workers, who wear overalls and red roses and like to call themselves "the Effluent Society." The week began inauspiciously in South Bend. Muggy weather sent several dozen Airstreamers to the hospital with heat exhaustion, and at least one participant died during the week. Another man was hit by lightning, though not seriously injured. Rainstorms turned the parking field into mud bogs, and there were two tornado watches in the Michiana area.

The Airstreamers have come here from nearly every state and Canadian province to celebrate the unique vision of their club patriarch, the late Wally Byam of Los Angeles, who, it happens, was born on the Fourth of July. It was Byam, a Stanford graduate and former shepherd in Oregon, who first conceived the name "Airstream" in 1936 when he introduced a new line of travel trailers featuring riveted aluminum shells. Drawing from technological advances in the airline industry, Byam's special aerodynamic bubble was designed to ride "like a stream of air." The silver pod was dubbed "the shape of the future," and in the postwar boom Airstream became wildly successful, etching itself into the popular culture both as a product and a way of life. NASA has used Airstreams as decompression chambers for astronauts returning from space. The Smithsonian houses an Airstream in its permanent collection. And today the Airstream is still considered the Cadillac of the RV industry, with a mystique all its own.

But Byam wasn't just a designer and businessman -- he was traveler himself, a latter-day Bedouin who believed in the high romance of group touring. He wore a blue beret, his sartorial trademark and now the club's official headgear. He caravaned around the world in a special gold-plated Airstream with an observation hole punched through the roof, where he liked to perch himself, like Hannibal atop his elephant, and shout instructions to his fellow campers through a bullhorn.

Byam's caravans were legendary. Once he pulled a team of Airstreamers through Africa -- from Cape Town to Cairo. In Ethiopia, he gave an Airstream to Emperor Haile Selassie as a gift. Another caravan took him and a large group of friends to Central America along the Pan-American Highway. These caravans served as field trials for the early models. Byam would send telegrams to the company engineers, requesting additions or structural changes in future models based on his far-flung road trips.

Byam also drafted a kind of traveler's prayer, called "The Wally Byam Creed," that Airstreamers will recite to this day: "To place the great wide world at your doorstep for you who yearn to travel with all the comforts of home. ... To keep alive an enduring promise of high adventure and faraway lands. ... To lead caravans wherever the four winds blow, over twinkling boulevards, across trackless deserts ... to the traveled and untraveled corners of the earth. ... To strive endlessly to stir the venturesome spirit that moves you to follow the rainbow to its end."

"It's a lifestyle that gets into your blood," says Gene Stubbs of Vienna, Va. A strapping, amiable man with a bolo tie and a model Airstream bulging from his belt buckle, Stubbs is president of Region 2 of the WBCCI, a large domain that extends from Ontario to Maryland and includes the District of Columbia. On a bright afternoon here, he sat in his 1990 34-foot Limited -- Airstream's top-of-the-line trailer -- sipping Cokes with his wife, Shirley, and extolling the virtues of caravaning. "I got an Airstream because it was the only RV I could stand up in," jokes the 6-foot-5 former Department of Defense contractor, noting that he's installed a customized seven-foot bed in the trailer's bedroom.

The Stubbses' new rig has got all the options: Corian counter tops, oak cabinets, a cedar-lined closet, mixer, microwave, blender, color TV -- the works. It's a cheerfully decorated world, with an Astroturf welcome mat and a needlework greeting hanging by the door that says, "Home Sweet Home." The magazine rack is stashed with copies of Trailer Life and the Blue Beret, the club's monthly journal. Everything inside here folds out, slides in, tucks under and snaps down. "A marvel of space utilization," Stubbs calls it.

He points out that every WBCCI member is issued an all-important ID number that is placed conspicuously on each trailer. If a member spots another Airstream driving down the road, he can look up the number in a membership directory and find out who's driving and where they're from. "With Airstream, you have instant friendships," says Shirley Stubbs. "People come up to you from out of nowhere and say, 'I'm an Airstreamer too.' It's a big silver magnet that draws people together."

The Wally Byam Caravan Club was organized by a group of Byam's friends who were taken with his romantic notion of self-sufficient travel and thought the caravaning lifestyle might especially appeal to retirees, who had the leisure time and disposable income to travel year-round. The first International Rally was held in 1958 in Bull Shoals, Ark. The Airstreamers parked in a giant wheel formation, like a wagon circle from the Wild West days. Just 300 trailers showed up that first year, but the word spread, and membership grew exponentially.

RVing is a declining lifestyle these days, even as America ages. Airstream's major competitor, Avion, suspended operations last year, and most other manufacturers have been sustaining heavy losses. Airstream's membership has significantly declined since the mid-'70s, and the club has a natural attrition rate (on average, 350 WBCCI members pass away each year). But unlike other RVs, Airstream draws committed caravaners who are less likely to drop out with the vagaries of the economy or increases in gasoline prices. Today the WBCCI has more than 15,000 member families.

Edna and Les Covar of Melbourne, Fla., have lived year-round in their Airstream for 19 years, a lifestyle known within thew subculture as "full-timing." "At first, I didn't think it was possible," Edna says. "You know, I just figured you'd get claustrophobia in there, living all year long. But I adjusted real quick. We're not supposed to use the word 'gypsy,' but I guess I'm a gypsy at heart. I don't even like to stay anywhere else but my Airstream anymore."

Airstream continues to hold a peculiar fascination for students of American iconography. Here at Notre Dame, a TV crew with NBC News has been filming the rally in connection with Jane Pauley's forthcoming prime-time series on Americana. Another crew from Ithaca, N.Y., is here to film a lengthy documentary on "Aging in America," and will be caravaning with Airstreamers for several weeks in Glacier National Park. And at the Divinity School at Notre Dame, a class on "Ritual Studies" has been discussing the Airstream way of life taking place just outside its windows.

At its very essence, the WBCCI is a club built around a shape.

Only owners of the classic bubble-shaped aluminum Airstream are eligible for membership. (Some Airstreamers jokingly refer to other makes as SOBs, meaning Some Other Brand.) "It's the style that we like," says incoming WBCCI President Ed Minty, who theoretically lives in Phoenix but has been on the road for three years now with his wife, Pat. "The Winnebagos and all these others, they're good trailers. But they don't have that classic look about them. It just looks different. It's that aluminum -- it gives. It's flexible. Boy, that thing's alive!"

The current debate raging within the WBCCI is whether the club should officially open its ranks to the owners of a new box-shaped trailer manufactured by Thor Industries of Ohio, Airstream's parent company. WBCCI purists call the controversial newcomer a "Squarestream" and have so far succeeded in blocking its admission. "We don't mean to be arrogant about it," says Bill Taylor of Nashville, Ind., a longtime owner of a Land Yacht Airstream. "But once you open the door to one model, all the standards go out the window. You have to draw the line somewhere, or else everybody will want to start calling himself an Airstreamer."

"There's nothing in the world wrong with the so-called Squarestream," says Mary Tinga. "It's just as cute as it can be. But it's just not ... well, it's just not round."

Her husband, Eelco Tinga, likes to explain the club's obsession with roundness this way: "If you go by a pasture where there's Holstein cows, they're all black and white, and it looks good. If you go by another pasture where they're mixed in with Jerseys and Guernseys and beef cattle, they look -- pfffft. Right? See, this is what we like about what we've got here. Uniformity. Everything looks the same."

But it's not just aesthetics, of course. Airstreamers insist that the aerodynamic shape and lightweight aluminum construction diminish wind drag and increase gas mileage by as much as 20 percent. "You've got to make a hole to drive through," Eelco Tinga explains. "With the Airstream, you make a nice round hole in the air. You get great towability. That thing just pulls along smooth, and you forget it's back there."

Bill Taylor's wife, Betty, has attended all 33 International Rallys, and worked full-time for Airstream for 14 years. "We're just die-hard travelers," she says. "Oh, we have a home, and it's a nice home too. But we like to know what's on the other side of that hill, around the next corner, over that mountain range in the distance. And then when the day is done, we like to sit down with our friends in our lawn chairs beneath the awning here, and just talk about it."