A description and photographs of Whitehead's aircraft appeared in Scientific American in June 1901,[1] stating that the "novel flying machine" had just been completed, and "is now ready for preliminary trials".

Propulsion was then changed to a 20 hp (15 kW) acetylene engine driving two counter-rotating tractor propellers mounted on outriggers.

A description and photographs of Whitehead's aircraft appeared in Scientific American in June 1901,[1] stating that the "novel flying machine" had just been completed, and "is now ready for preliminary trials."

Whitehead was quoted in a July 26 article in the Minneapolis Journal, credited to the New York Sun, in which he described the first two trial flights of his machine on May 3.

According to Whitehead, the machine flew a distance of 1/2 mile (790 m) during its second test flight for one and one-half minutes before crashing into a tree.

He also explained his desire to keep the location of any future experiments hidden to avoid drawing a crowd who might make a "snap-shot verdict of failure".

[2]In an article in the August 18, 1901, issue of the Bridgeport Sunday Herald a reporter states that he witnessed a night test of the machine, at first unpiloted and loaded with sand bags, and later with Whitehead at the controls.

According to Whitehead and a reporter who claimed to have witnessed the event, the monoplane's longest flight was 200 feet (61 m) above ground for one-half mile (0.80 km).

[7] Tom Crouch, senior curator of aeronautics for the National Air and Space Museum (NASM) of the Smithsonian Institution, studied evidence for the alleged flight and in 2016 he issued a strong rebuttal, noting many other authorities who had already done so.

[9] In 1986 American Andrew Kosch, a local high school teacher and hang glider pilot, led a team which built a replica of Whitehead's No.21.