It has been almost 45 years since Amelia Earhart left Lae, New Guinea, in her twin-engine Lockheed Elektra 10E, and flew off into a vacuum of history and mystery.

Before departing from a 3,000-foot runway hacked out of a jungle clearing on what was to be the third-to-last leg of an earth-circling trip, she had written, "the whole width of the world has passed behind us except this broad ocean. I shall be glad when we have the hazards of its navigation behind us."

Twenty-two hours and 45 minutes later, Earhart radioed, "We are running north and south." She was never heard from again, at least formally, and in the relatively simple act of disappearing, she forged her own strange immortality.

Yesterday the Air and Space Museum, which owns the Lockheed Vega that Earhart flew across the Atlantic 50 years ago, sponsored a public symposium on the first woman to make the solo voyage across the Atlantic (a journey she made five years to the day after Charles Lindbergh's flight). In piecing together the tales told at the symposium by six individuals whose lives were touched by Earhart, one was confronted with a fairy-tale romance which, if examined too carefully, makes Earhart's own life seem less fascinating than it remains now, half-shrouded in myth, half grounded in the reality of metal wings and gasoline.

Muriel Morrissey, Earhart's sister, recalled the family's roots in Atchison, Kan., where the two girls were raised in gym suits instead of skirts and were given footballs and rifles by their father Edwin, a railroad executive who took the family on delightful trips in a company Pullman reserved for his use.

Fay Gillis Wells, a close friend of Earhart's and founder of an organization for women pilots, told of her early days in the air, when Earhart abandoned Columbia University and her dreams of being a doctor after seeing planes flying around Toronto in 1918. In a Kinner Airster biplane she took lessons from Netta Snook, whose fees were paid from wages Earhart earned in a Los Angeles telephone office.

Rear Adm. Richard B. Black recounted the long night aboard the U.S. Coast Guard Cutter Itasca, which was cruising near Howland Island, the one-by-three mile Pacific atoll where Earhart and her navigator Fred Noonan were expected to land and refuel for the next leg of the trip, which would have taken them on to Honolulu.

Elgen Long, a commercial pilot, spoke of the 40 years of his life that he has devoted to solving the mystery of Earhart's last flight. By analyzing her radio transmissions and route maps and from aerial surveillance of Howland Island, he has concluded that the Elektra ditched in the Pacific about 40 miles northwest of the island. Long has established a nonprofit foundation through which he hopes to locate and recover the plane.

Frederick Goerner, the author of "The Search for Amelia Earhart" expounded his own theory, that Earhart might have been spying for the Navy and was captured by the Japanese. He told of numerous reports by Japanese who had seen an American man and woman, said to be aviators, who were being guarded on various islands, and spoke of reports that the Marines had destroyed the Elektra, which some had said was parked near a runway on Saipan--all of these reports, he maintained, obscured by the government over the years to protect the nature of Earhart's mission.

Gordon Vaeth, director of satellite operations for the National Oceanic and Atmospheric Administration, told of his own six-year study of the matter, and his conviction that Earhart was not a spy, and that the government has never made an effort to cover up anything regarding the flight.

Yesterday, there were tales of hidden cameras, of ham radio operators in California picking up transmission from Earhart about Japanese soldiers approaching the plane, of a grave exhumed on Saipan and of private detectives who spent lifetimes trying to figure out what really happened.

All that seems certain is this: Amelia Earhart flew into history, and the mystique that surrounds her is as basic as the wonder in the eyes of a child, trying to comprehend how a piece of metal can fly into the sky with the grace of a bird.

Her life was a testament to that mystery, and perhaps to the quality that sends men into space on rockets, expressed in a poem she once wrote:

Courage is the price that life exacts for granting peace.

The soul that knows it not, knows no release

From little things;

Knows not the livid loneliness of fear

Nor mountain heights, where bitter joy can hear

The sound of wings.

How can life grant us boon of living, compensate

For dull gray ugliness and pregnant hate

Unless we dare

The soul's dominion? Each time we make a choice, we pay

With courage to behold resistless day

And count it fair.