The blinking red button on Tom Benson's madras shirt wishes you a Happy Fourth of July as he talks about the third time he encountered aliens. Many people misunderstand flying saucers, he says from behind his vendor's booth at the 30th annual Mutual UFO Network (MUFON) symposium being held this weekend in the Crystal City Hyatt Regency.

"The vehicle's not physical. It's an energy construct," explains Benson. "It's your consciousness or soul that gets taken on board."

Benson, 61, works for the state of New Jersey as a personnel management analyst but has a sideline selling vintage UFO books. A patriotic fellow, he's set up several American flags amid his wares, and this weekend is offering a special on a plastic "Dashboard Uncle Sam With Flag" for $3.

It would be tidy to conclude that Tom Benson represents something "typical" about this convention, which is open to the public and expected to attract about 500 people through tomorrow. But there is nothing typical about MUFON. Here we have humans who claim to be infused with alien consciousness and receive messages from other galaxies. Here are researchers who believe they have bettered Einstein and uncovered the secrets of "extraluminal" (beyond light speed) physics.

What could be more all-American than the participants' passion, the intense debate and yearning to be heard? At a news conference yesterday--attended by exactly one mainstream newspaper reporter and about 50 conventioneers--panelists from around the world defended their research papers, addressed a schism in the movement and criticized the media.

"They tend to view us as an interesting sociological phenomenon--and we end up on the Style pages," lamented Richard H. Hall, whose saucer investigations date to the mid-1950s. "I'm very empirically oriented. We need to get back to basics."

For some, UFOlogy has become a New Age religion. One constant controversy pits those who embrace UFO "evidence"--the sightings, radar returns, declassified documents and eye-witness testimonials--against ethereal approaches that seem to construe space visitors as angels.

"We don't get involved with New Agers. We avoid them like the plague," says Walter H. Andrus Jr., MUFON's 78-year-old international director. "We're dedicated to the scientific study of the UFO phenomenon." He quickly adds, "The evidence is overwhelming that the abductions take place."

Yet Andrus admits he has never seen one tangible piece of actual evidence--say, an exhaust pipe from an extraterrestrial craft--emerge in decades of UFO studies.

No matter. UFOlogy is among our most durable, high-tech industries, taking off in 1947, concurrent with the so-called Roswell incident and the development of the early computer, ENIAC. Saucer sightings fueled an entire Hollywood film genre, featuring space beings whose essential personalities shape-shift depending on our cultural mood--from the benevolent Klaatu in "The Day the Earth Stood Still" to the malevolent squid monsters in "Independence Day" to the current nonsymbolic, merely annoying Jar Jar Binks.

This weekend, all the movement's most quoted mouthpieces are in town--among them Stanton T. Friedman, who calls himself the "original civilian investigator of the Roswell incident," a reference to the purported crash of an otherworldly vehicle in New Mexico. But the star of the conference is a newcomer with a neatly trimmed beard and a nice blazer: Joe Firmage, 28, a Silicon Valley entrepreneur.

Firmage is an important figure not just because he espouses a new, unified, alien-oriented theory--which he modestly calls The Truth--but because he is loaded. Worth, some whisper, about $200 million. That bestows a certain instant credibility. Firmage founded USWeb Corp., but his new intellectual pursuits prompted a hasty exit as CEO.

"I have reached the conclusion that UFOs are real," Firmage said. He admitted he's never seen a UFO--or, as frequently reported, actually spoken with a space creature. "What I said was that I had a conversation with a being of light. I didn't say 'alien.' I didn't say an organic body." (For more on Firmage, his talk is at 8:45 tonight.)

Susan Swiatek of Fairfax, the symposium coordinator, also says she's never had a close encounter, but she's dedicated all her spare time to setting up this convention for the believers--and anyone who might marvel at the endless possibilities of a clear night sky. "At MUFON we'll have fun, glow-in-the-dark aliens!" she promises. "It's an alternative if your beach plans fall through."

UFOlogists, like most Americans, are questers, she says; they yearn to be part of something more.

"I, personally, do not claim to have seen a UFO," Swiatek, 41, said. "I saw something so far away, it could have been a kite or something."

And you never know. Go out and look in the sky this weekend. You might notice something glowing. You might see things that sparkle, swoop, arc and fly. You might see something that reflects what it means to be an American.

CAPTION: Flying saucers are sorely misunderstood, says Tom Benson, at the UFO convention in Crystal City.

CAPTION: Joe Firmage, left, and Bruce Maccabbee at a news conference yesterday at the UFO convention.