The prototype space shuttle Enterprise came to the Washington area yesterday, and, to some, it was the biggest nonevent since Comet Kohoutek failed to destroy the earth in 1973.

"Yeah, I'm waiting for the shuttle," said Jim Hastreiter, standing in front of the Bureau of Engraving on 14th Street. "I'm waiting for the shuttle to the employe parking lot."

Like many Washingtonians yesterday, Hastreiter, who works for the Department of Energy, had a tough time keeping a straight face when he was told that the Enterprise was about to fly piggyback on a Boeing 747 around the Capital Beltway and cross the Cabin John and Wilson bridges before proceeding up the Potomac to land at Dulles International Airport.

About 4:47 p.m., the crafts glided to a safe landing at Dulles after swooping low across 10 East Coast cities coming up from Kennedy Space Center in Florida. Hundreds of curious spectators gathered on the observation deck at Dulles to view the landing of the shuttle, which will go on permanent display at an annex to the Smithsonian's National Air and Space Museum.

"It's exciting," said Charlotte Dobies, 42, of Sterling, who drove to the airport to show her 9-year-old son the shuttle. "It's good to see it on TV, but it's special to see it here."

"It's great," said Donald S. Lopez, deputy director of the National Air and Space Museum, who watched the 747 touch down on the runway. "It feels wonderful."

But back in the District, the flyover of the shuttle created little excitement.

Even the unusual sight of one commuter pulling to the side of the 14th Street bridge, leaping from his blue BMW, and pointing to the deeply overcast heavens, couldn't stir much emotion.

"Is he for real?" asked Joyce Milner, an employe of the Department of Agriculture.

"I mean if it actually showed up, I would love it, of course, but what kind of joke is this?" Milner said.

Then it happened, sort of.

"That's it, that's it -- it's a 747 with a plane on top of it," shouted Michael Martino, who also works for the Department of Agriculture. "It's as plain as anything."

"What's this all about, anyway?" asked one cab driver who had just returned from Dulles. "Don't we see enough planes around here?"

The Enterprise was not built to fly in space, but was used instead as a test craft at Edwards Air Force Base in California in 1977.

It had been seen in Washington once before, in June 1983, when it was on the final leg of a 16,000 mile public relations tour that included the Paris Air Show.

When NASA no longer needed it, the Smithsonian gladly accepted it.

However, it will be another three or four years before the Enterprise is on public display.

What's needed is a facility in addition to the one on the Mall to accommodate such treasures as the 122-foot long shuttle.

Already, the National Air and Space Museum, the world's most popular museum, is so crowded that it can exhibit only 75 of the 320-odd aircraft in its possession, and about the same number of spacecraft, Lopez said.

Museum officials hope to receive congressional authorization and funding to build a four-building museum annex, costing $87.6 million on 180 government-owned acres at Dulles, Lopez said.

The buildings would house the Enterprise, as well as other large Smithsonian-owned craft that are currently on loan to other museums or in storage.

For now, however, the shuttle will remain at Dulles, along with mothballed B17 and B57 bombers that belong to the Smithsonian. The other airplanes are kept outdoors, but the shuttle will receive its own temporary Quonset hut-type structure, Lopez said.

"It's because of its great value," he said. "And, it's much newer than the others."

The shuttle was originally scheduled to reach Washington by early yesterday afternoon, but the flight from the Kennedy Space Center in Florida was delayed two hours until the early morning fog burned off so more people could see the craft along the way.