With the stately brass and insistent drums of Aaron Copland's Fanfare for the Common Man," the Kennedy Center last night opened its tribute to five uncommon Americans.

In receiving the second annual Kennedy Center Honors -- a tribute for "lifetime achievements in the performing arts" -- Copland was joined by Ella Fitzgerald (who, in the words of the citation, "could sing the telephone directory and make it sound good"), Henry Fonda (who "for much of the world, has been America"), Martha Graham (who was introduced by Gene Kelly as the spearhead of "a revolution in American dance") and Tennessee Williams ("our most prolific playwright . . . our most popular dramaist").

To keep the evening from becoming too one-sidedly esthetic or intellectual the program included an early appearance by Art Buchwald, who hailed the occasion as "the second year that Washington claims to have any culture."

Addressing most of his remarks to Rosalynn Carter, who, wearing peach chiffon and escorted by Sen. Edmund Muskie (D-Maine), represented the absent president, Buchwald reminded her that "when I spoke to you last year in this beautiful building, the roof was leaking." Buchwald made it clear that, besides conferring something like knighthood on its five recipients, the honors ritual was designed to raise money for the Kennedy Center.

"This year," said Buchwald, "I am happy to report, the roof has been fixed. Please tell the president that we only need money now to pump water out of the cellar."

At the reception after the Kennedy Center honors, hordes of stars were literally herded to the 150 tables placed in the Grand Foyer at the Hall of Nations. "Tables one through 44 go straight ahead," yelled a waiter giving directions. While he shouted, an orchestra played "Three Dances" by Tilman Susato.

"We put them down here because we couldn't fit them in the atrium," said a Kennedy Cente employe, looking across the packed tables where diners sat under enormous glass chandaliers, dropping food on the Kennedy Center's red carpet.

A small, intimate but rather brightly lighted cabaret room was also set up backstage in the Concert Hall. Appropriately called "Le Cabaret," it had exactly the right kind of tackiness in its decoration -- long strings of tinsel concealing a cement pillar, potted ferns hanging from the ceiling, small tables and a revolving ball with many facets shooting streams of light in all directions. In this room, music was supplied by Peter Duchin and his band.

The food, which was seafood creole, rice, carrots and assorted cheeses, took a while to get. That was because everyone stood in mammoth lines. "Why couldn't they serve us hamburgers?" piped up a voice in the crowd.

Ethel Kennedy, who wasn't at the White House, surfaced at the reception. It was easy to find her, because like her brother-in-law the candidate, she was surrounded by flashbulbs.

Ethel, who has campaigned for Ted in Alabama and Iowa, said the reception she received in Alabama was "very warm and enthusiastic."

And how was it in Iowa? "Would you excuse me for a minute?" she replied.

In another part of the dining area was Ella Fitzgerald, eating creole. "This is just one of those nights that you never forget," she said. "Never."

Within shoutng distance of her was Aaron Copland. "It feels pretty good he said, adding that he's taking life easy these days. "When you get to be my age -- I'm 79 -- you're less ambitious. You relax. You really deserve the right to relax, having spent 50 years writing music."

Many of the 2,000 people at the tribute had come over from the White House, where a glittering reception was held earlier for the honorees and about 500 friends. As the movie stars and political stars rubbed mink-draped elbows, it was hard to tell who was more awe-struck.

"Somebody just told me Gene Kelly went by -- just whoosh, like that," said a thrilled Cece Zorinsky, wife of the Nebraska Democrat. "I'm so excited. I'm his biggest fan."

"Can we sit down?" asked a nervous Michael Moriarty, the actor who with his wife, confessed to first-time-at-the-White-House butterflies.

President Carter canceled out of the reception, but First Lady Rosalynn Carter stepped in to substitute, welcoming the throng to the East Room in her husband's absence.

"The president has had to cancel every one of his appearances in this time of crisis," Mrs. Carter told the crowd, which included the five honorees.

"It's the greatest honor I've ever received," Williams said. "Those Pulitzers are a dime a dozen."

The honorees were disappointed that the president wasn't there. "But if he had been here," Copland said, "I would have told him I was surprised to see him."

The uncertainty surrounding the event because of fast-breaking developments over the hostages in Iran meant that "we've been on and off," said White House social secretary Gretchen Posten. "Our invitations didn't go out until two weeks ago."

The guests, who wore minks and diamonds and were a booking agent's dream included actresses Lillian Gish, Elizabeth Ashley, Ann Miller, Gwen Verdon, Meryl Streep, Lynn Fontanne and Jean Stapleton; actors Alan Alda, Kelly, Moriarty and Mickey Rooney; musicians Count Basie, Tony Bennett, Earl "Fatha" Hines and Art Garfunkel; media celebrities William paley, Eric Sevareid, William Leonard, Rowland Evans and Katharine Graham.

Rosalynn Carter and Joan Mondale welcomed the guests in a long receiving line in the Grand Foyer.Flash bulbs winked, sequins glistened, and for several hours, at least, a tense White House became like a scene from a movie opening.

Everywhere you looked were stars. Designer Halston, suntanned from a recent weekend in Montauk, sat with Martha Graham in the Red Room. She wore one of his dresses, a green filmy affair that matched the ribbons she wore as an honoree. "You'd almost think I designed it for tonight," Halston said.

Nearby was Tennessee Williams. "I'm not very gregarious," he said. "I like small parties by candlelight. But if it's a big party, I like it at the White House."

At this point, Lillian Gish came floating up to Martha Graham. "Darling," the two said in unison.

One guest who definitely stood out from the others was a road manager to Elizabeth Ashley who wore a cowboy hat and shoulder-length hair and had a miniature Harley Davison motorcycle on his earlobe. His name was Philip "Mangler" Kaufman, but he introduced himself as Elvis Presley. "This is only the second time in my life I've had a tuxedo on," he said, "and you know what's nice about tuxedos? All us jerks look alike. You can't tell a senator from a bass player."

Alan Alda, who presented a very dim view of Washington politics in his movie "The Seduction of Joe Tynan," said last night that he didn't really hate the nation's capital. "I don't hate Washington," he said. "I love Washington. I just don't like politics."

There were top-level White House aides in the crowd, including Anne Wexler and Lloyd Cutler, but comments about the president's absence were met with stony silence.

FBI Director William Webster came up to Cutler in the Blue Room to tell him that early yesterday morning, while he was working on arrangements to move the shah from New York to a Texas Air Force base, a gun went off next door.

"A man was killed in a house break-in, so I spent most of the day helping solve that," Webster told Cutler.

Webster said that he had been in San Antonio three days ago for another reason but that he understood by last night television stations there were speculating that his visit had been in connection with the shah's move. He laughed, telling Cutler that it hadn't been.

"So the move was sudden? someone asked Webster, who didn't answer.

The Kennedy Center Honors were established to give "recognition to individuals who through their lifetimes have made significant contributions to American culture through the performing arts." In addition to this lofty verbiage, they also have been established to raise money -- lots of it. Last night, Kennedy Honors producer George Stevens Jr. said he expected about $400,000 to come from the event. It will all go to the Kennedy Center, which needs it.

As usually happens when people partake of the president's buffet table at the White House, guests there had nothing but praise for Jimmy Carter. In this case it was for his handling of Iran.

Carter pollster Pat Caddell said he didn't know how Iran would effect Carter's standing in the polls.

"Nobody knows. It's one of those situations of international crisis when politics is irrelevant and candidates become irrevelant," he said, adding that he wouldn't take a poll until the Iranian situation is solved.

"All I have seen has been grace under pressure and strength with reason," said Elizabeth Ashley.

"I think the president is doing the only thing at the moment that he possibly can do," said Elizabeth Taylor Warner.

Spotted here and there around the buffet table was actress Cloris Leachman. "I was being a good girl for the first 45 minutes," she said, apologizing for her rapid consumption of finger sandwiches.

At her elbow was still another actress, Jean Stapleton. She wore a black velvet turban with glistening rhinestones. "It's really easy when your hair is a mess," she said.

Chip Carter said it wasn't just because of the Iranian crisis that Ted Kennedy seemed to have disappeared from the front pages. "Everybody knew as soon as Kennedy announced, he'd go down in the polls," the president's son continued. "My grandmother gets on the front page. We haven't muzzled her, but we've talked about it.Those things, you know, are said in jest -- there was laughter and applause -- but when it's covered as straight news, something gets lost.

"She would not spend a million dollars to have somebody knock him (the Ayatollah Ruhollah Khomeini) off, either."

"Is she too tight?" he was asked.

"Probably," Carter said, laughing. "The whole Carter family's tight."