Rewriting the history of flight. Did Gustave Whitehead, an obscure German immigrant in Connecticut, make and fly the first powered airplane some 2 years before the Wright brothers' historic 1903 flight at Kitty Hawk?

AS researcher, historian, archivist, and detective, Maj. William O'Dwyer has spent the past 23 years piecing together evidence that, if found true, would send aviation history into a tailspin. If true, the Wright brothers would lose their place as the first to successfully engage in powered flight. That laurel would pass to an obscure German immigrant named Gustave Whitehead, who lived in Connecticut at the turn of the century and currently occupies a mere footnote in aviation history.

According to old newspaper clippings, magazine articles, and eyewitness accounts collected by Major O'Dwyer and other researchers, Whitehead flew under power a distance of about 2,500 feet on Aug. 14, 1901 - some 2 years before the Wright brothers' 1903 flight at Kitty Hawk.

The original plane, called ``No. 21,'' was created from bamboo, silk, and piano wire and resembles a kayak with wheels and what looks like large bat wings. O'Dwyer and a group of flying enthusiasts built a replica from photos and this past March made a successful tethered flight of the craft. A powered test flight, duplicating in every way Whitehead's supposed 1901 flight, is expected sometime next year.

Peter Jakab, curator of the Smithsonian Institution's National Air and Space Museum, which exhibits the Wright airplane, said in a telephone interview from Washington, D.C. that Whitehead was ``a participant'' in early aviation ``but not a significant pioneer.''

``He built airplanes and engines,'' says Mr. Jakab, ``but none had any success. There is no proof.''

``No proof?'' grumbles O'Dwyer. ``We have over 20 eyewitnesses on affidavit who watched him fly; we have the original eyewitness report by the editor of the Bridgeport Sunday Herald in 1901; and we have the Scientific American saying he flew.''

A series of articles in the prestigious Scientific American magazine does credit Whitehead with early flights. In a September 1903 issue, for example, reference is made to a flight of Whitehead's tri-plane ``that was made to skim along above the ground at heights of from 3 to 16 feet for a distance, without touching the ground, of about 350 yards.'' Later issues in 1906 and 1908 speak of Whitehead's 1901 flight with motor-driven airplanes as historical fact.

The Bridgeport Sunday Herald of Aug. 18, 1901, describes the plane in the 1901 flight looking like ``a great white goose rising from the feeding ground in the early morning dawn.''

Smithsonian's Jakab dismisses the Scientific American story as referring to hang gliders, not powered aircraft. He says the author, Stanley Beech, later admitted Whitehead had never flown. Whitehead, he says, is one of a dozen people who claim they flew before the Wrights.

O'Dwyer says the real reason the Smithsonian refuses to recognize Whitehead's contribution involves a cover-up.

About 10 years ago, and with the help of Connecticut Sen. Lowell Weicker Jr., O'Dwyer got a copy of a secret contract between the Smithsonian and the estate of Orville Wright.

The contract revealed a surprising clause: The Smithsonian would receive the Wright airplane in exchange for $1, provided the Smithsonian would never display any aircraft ``of earlier date than the Wright Aeroplane of 1903, claiming in effect that such aircraft was capable of carrying a man under its own power in controlled flight.''

Jakab admits the contract exists, but says the clause had nothing to do with Whitehead. Rather it was to prevent Charles Langley, the first secretary of the Smithsonian and a rival of the Wright brothers, from claiming that he was the inventor of motorized flight.

``The Smithsonian,'' says Jakab, ``would never deny truth to hold on to some artifact.''

``But you see, that's history by contract, and not history by fact,'' counters O'Dwyer. ``They have a vested interest in the Wright plane. If the contract is broken, Smithsonian will lose the plane.''

``We want a public hearing,'' says O'Dwyer. ``We've invited the Smithsonian to attend. What started with eight typewritten pages on Whitehead today occupies 10 file drawers full of material - material that proves Whitehead deserves a hearing.''

The Smithsonian's official reply? ``A public forum is not an appropriate forum for scholarly inquiry.''

Robert Stepanek, president of the Connecticut Aeronautical Historical Association, supports O'Dwyer's call for a hearing of ``knowledgeable aviation historians and aeronautical engineers.''

``Whitehead may have flown,'' he says, ``we're not in a position to say one way or the other. It really involves a definition of flight. He got his craft into the air and landed it at a point no lower than the point of takeoff. But was he in control of it? We don't know.''

Whitehead came to New England in 1894 and worked in such jobs as auto mechanic, truck driver, kitemaker, and night watchman. In Connecticut, he made gliders and engines.

The Connecticut Aeronautical Historical Association calls Whitehead, who died in 1927 and is buried in Bridgeport, Conn., ``the father of Connecticut aviation.''