In the end it is wonder that draws the young and old to Gravelly Point, a little-known name for a stretch of National Park Service land just north of 18/36, National Airport's main runway.

"Here it comes, here it comes," shouts a little girl in pony tails. "See the light? Here it comes!"

"Yeah," replies her little brother as he runs about the park lawn. He places himself directly under the headlights of a plane taking off from National Airport. Together they jump up and down, eyes aglow, faces amazed.

A sleek 727 rolls faster and faster down the runway, the screech of exhaling jet engines becomes louder and the huge oblong object becomes even more huge. Suddenly, the plane is directly overhead, within the distance of a long stone's throw.

The deafening burst of engine thrust rattles their bodies and quakes the soil underfoot. They cannot even hear themselves speak.

Brother and sister exchange "ahs" and "ohs" but some other children run in terror and tears to the security of their parents' arms. Adults gaze upward, looking at the details of the plane's belly. Although they cannot see the pilot or the passengers behind the opaque windows, a small red light blinking between the wheels is within clear sight.

After the massive structure of airborne metal passes by at more than 200 mph, a deep grrrrrrrr rumbles through the sky from behind the plane, the music of thunderheads.

One by one, the planes zoom, and the marvel of flight instills awe on how man has learned to hurl more than 100,000 pounds of metal into the air.

On weekends, the lawns of Gravelly Point, bordered on two sides by the Potomac River, are like those of a countryside race track. Families with picnic blankets, passersby on bicycles, tourists and motorists--they all come to watch man and machine race through the sky.

A little girl sucking her thumb and her brother snuggle in close to their mother as passenger jets landing and taking off roar overhead.

"They think the plane's going to land on top of their head. So they stay pretty close to me," said Susan Glick, 29, mother of 3-year-old Aaron and 21-month-old Renee, of Silver Spring.

After dropping off Aaron's grandparents at the airport, Glick made her first visit to the point recently. "This is big excitement for them," she said.

The kind of excitement, it turned out later, that it was hard to even think about leaving.

"You guys seen enough?" asked Glick, who wanted to call it a day.

"Nope, I want to see lots of airplanes," replied Aaron.

But it is not only the children who find fascination at the end of a runway. For the past six or seven years, Frank Gumpert of Potomac has seen lots of airplanes come and go. Frequently during the week, he avoids some of the rush-hour traffic when he returns home from work at his printing shop by stopping off at the Gravelly Point lot. He buys a refreshment from the concession stand and ponders the spectacle of flight.

"I think of the enormous power lifting all those people off the ground. It's very exciting," said Gumpert, who is in his mid-50s.

"Look at this," he exclaimed, pointing to a plane approaching liftoff. "Look at the nose. Look at the power of that takeoff. There's 250 people aboard that plane . . . ." The rest of his words are drowned out in a sky filled with engine roar.

Another plane is landing at the far end of the runway. "Straighten it up," he commanded, pretending to speak to the plane's pilot. "You know I'm talking to him as he's landing to make sure he does it right."

Another plane is landing. "He's having a problem," Gumpert said. He explained that the plane suddenly floated above the runway from a shift in drafts. "I bet he's got a lot of people pushed forward in the cabin," he added jokingly.

Gumpert said some spectators bring a radio that can tune in to the airport's control tower. "I listen to the radio and that adds a little something to it," he said.

Not everyone looking skyward came specifically to watch the planes, of course. For some, the spectacle fills a moment caught between other pursuits. Bicycling buddies David Grooms, 30, and John Joiner, 35, both of Alexandria, use Gravelly Point mostly as a place to buy a soft drink on their trip to the Mall.

"When I do stop, I have to admit I watch the airplanes," said Grooms.

The neck-craning and engine thunder can take its toll on spectators. Echoing a sentiment expressed by other observers, Grooms said, "If you stay too long, it gives you a headache."

But the avid thinkers on Gravelly Point seem immune to such mortal problems. Gumpert said he never gets headaches during his lofty reveries on flying. Once in a while, though, his thinking comes out of the clouds and takes a more down-to-earth turn. Gumpert breaks out in a guffaw and jokes, "There's often the thought, what if he doesn't make it? Which way are we going to run?"