The Mignet HM.14 Flying Flea (Pou du Ciel literally "Louse of the Sky" in French) is a single-seat light aircraft first flown in 1933, designed for amateur construction.

It was the result of his ambition to design a safe aeroplane that could be built quickly and cheaply by any amateur familiar with simple woodwork and metalwork skills.

In the following months, he made many flights with progressive modifications to improve its handling and performance, totalling 10 hours test-flying time.

[1] In September 1934, the French aeronautical magazine Les Ailes published Mignet's article Le Pou du Ciel, in which he described the HM.14.

In November 1934, he published his book Le Sport de l'Air that gave all the dimensioned details of materials, plus descriptions and techniques, to enable readers to construct and fly their own HM.14s without further specialist help.

In September 1935, the Air League published an English translation of Le Sport de l'Air, and it was also serialised in the October, November and December 1935 issues of the magazine Newnes' Practical Mechanics.

On 24 July 1935, the Air Ministry awarded it the first ever Authorisation to Fly document, being equivalent to a UK Certificate of Airworthiness with additional conditions and limitations.

[1] By March 1936, Algerian and Swiss authorities had banned the flying of HM.14s, and the French Air Ministry stepped up its actions from cautionary notices to flight testing by the Armée de l'air, that resulted in an inconclusive published report.

In June 1936, the French Minister for Air stopped all Flea flights in France, pending full-size wind tunnel tests at Chalais-Meudon.

In late 1936, those features, together with rigid wing control struts ("push-rods"), were embodied in an updated edition of his book Le Sport de l'Air.

In August 1936, the Royal Aircraft Establishment (RAE) at Farnborough started full-size wind tunnel tests using HM.14 G-AEFV.