Controversy surrounds published accounts and Whitehead's own claims that he flew a powered machine successfully several times in 1901 and 1902, predating the first flights by the Wright brothers in 1903.

[7] According to an affidavit given in 1934 by Louis Darvarich, a friend of Whitehead, the two men made a motorized flight of about half a mile in Pittsburgh's Schenley Park in April or May 1899.

[16][17] The article, written as an eyewitness report, stated that Whitehead piloted his Number 21 aircraft in a controlled powered flight for about half a mile, reaching a height of 50 feet (15 m) and landing safely.

[28] He gave a description 33 years later of the engine and aircraft, including details of the steering apparatus: Rudder was a combination of horizontal and vertical fin-like affair, the principle the same as in the up-to-date airplanes.

"[28] In 1905, he and Stanley Beach jointly filed for a patent – issued 1908 – for an "improved aeroplane" with a V-shaped trough body and fixed bird-like wings, the pilot hanging below supported by a swing seat.

[36] Air Enthusiast wrote: "Weisskopf's ability and mechanical skill could have made him a wealthy man at a time when there was an ever-increasing demand for lightweight engines, but he was far more interested in flying.

The book said Whitehead had experimented with a "three-deck machine" and attached a 12 hp motor driving a tractor propeller after tests showed the craft could carry more than his weight.

"[37] In 1908, Whitehead designed and built a 75 hp lightweight two-cycle motor at the suggestion of aviation pioneer George A. Lawrence, who was having difficulty obtaining an aeronautic engine.

The water-cooled machine was designed so that functional cylinders continued to work if others failed, a safety factor to help avoid accidents due to engine failure.

One of his engines was installed by aviation pioneer Charles Wittemann in a helicopter built by Lee Burridge of the Aero Club of America, but the craft failed to fly.

Harvard University economics professor John B. Crane wrote an article for National Aeronautic Magazine in December 1936 disputing claims and reports that Whitehead flew, but he adopted a different tone the following year, after further research.

[43] In 1963, reserve Air Force major William O'Dwyer discovered photographs in the attic of a Connecticut house showing a 1910 Whitehead "Large Albatross"-type biplane aircraft at rest on the ground.

The Connecticut Aeronautical Historical Association (CAHA) asked him and his 9315th U.S. Air Force Reserve Squadron to investigate whether Whitehead had made powered flights.

[22] The editorial reignited debate over who flew first and motivated Connecticut to establish "Powered Flight Day" to honor Gustave Whitehead, rather than the Wright Brothers.

[23] He also attested to a January 1902 flight by Whitehead over Long Island Sound;[64] the 1988 Air Enthusiast article, however, said that "Pruckner was not present on the occasion, though he was told of the events by Weisskopf himself.

[65] The following are from the affidavits that Stella Randolph collected in the 1930s, quoted in part: I recall a time, which I think was probably July or August 1901 or 1902, when this plane was started in flight on the lot between Pine and Cherry Streets.

[71] A photo was displayed in the 1906 First Annual Exhibit of the Aero Club of America at the 69th Regiment Armory in New York City which showed an unpiloted Whitehead aircraft in flight.

The photo was mentioned in a 27 January 1906 Scientific American article[63] which stated that the walls of the exhibit were covered with a large collection of photographs showing the machines of various inventors.

"[48] Peter L. Jakab, National Air and Space Museum (NASM) Associate Director and Curator of Early Flight, suggested that the image "may very well have been an in-flight photograph" of one of Whitehead's gliders.

Researcher Susan O'Dwyer Brinchman suggests that Findley and Gardner hoped that the statement would help to defend the Wright brothers' primacy in flight against the recent challenge in Randolph's article and book.

The statement offered some words of praise, saying that Whitehead "deserves a place in early aviation, due to his having gone ahead and built extremely light engines and aeroplanes.

Popularly called a "contract," the agreement required the Smithsonian to recognize only the 1903 Wright Flyer, and no other aircraft, as first to make a manned, powered, controlled flight.

Brinchman documented that Gardner and Findley, who helped Orville rebut the Whitehead claims, also participated in crafting text in the agreement that the Institution is required to use in its labeling of the Wright Flyer.

"[98] This position is supported by Library of Congress historian Fred Howard, co-editor of the Wright brothers' papers,[43] and by aviation writers Martin Caidin and Harry B.

[101] Orville Wright, then in his seventies, countered the magazine articles by writing "The Mythical Whitehead Flight", which appeared in the August 1945 issue of U.S. Air Services,[102] a publication with a far smaller but very influential readership.

Orville discussed John J. Dvorak, a physics professor at Washington University in St. Louis, who had designed an engine and hired Whitehead to build it after praising him publicly.

21 aircraft might have flown, Connecticut high school science teacher Andy Kosch, a pilot, built a replica of the craft, using existing photos and blueprints created by experts working with O'Dwyer in a project called "Hangar 21".

A large headstone replaced the bronze marker of his grave at a formal dedication ceremony on 15 August 1964 attended by elected officials, members of every branch of the armed services, Clarence Chamberlain – famed aviator, CAHA, the 9315th Air Force Reserves Squadron, and surviving members of his family, his three daughters, and his assistant Anton Pruckner, commemorating Whitehead as "Father of Connecticut Aviation".

[107] A memorial fountain and sculpture commemorating Whitehead's "aviation first" was dedicated in May 2012 and was located on a traffic island at the intersection of Fairfield Avenue and State Street in Bridgeport[108] It was removed around 2023.

On 25 June 2013, Connecticut Governor Dan Malloy signed into state law House Bill 6671 recognizing Gustave Whitehead as the first person to achieve powered flight.