In 1894 he finished 17th in the world's first motor race, driving his Serpollet steamer from Paris to Rouen, covering the distance of 127 km (79 mi) in 13 hours.

He was encouraged to do this by the pioneer French aviator Captain Ferber, who had written to Archdeacon demanding "Do not let the aeroplane be achieved in America first."

[6] In 1903, Archdeacon commissioned an imperfect copy of the 1902 Wright glider[7][8] from Monsieur Dargent at the military balloons and airships workshop at Chalais-Meudon.

[9] It was a biplane with an ash framework covered with silk and braced with piano wire, and lacked the provision for lateral control that was the key to the success of the Wright Brothers' aircraft.

The aéroplane is very robust despite weighing only 34 kilograms.The first experiments with this glider were conducted in April 1904 on the dunes at Merlimont near Berck-sur-Mer, piloted by Gabriel Voisin and Captain Ferber.

[8] In October 1904, Ernest Archdeacon joined Deutsch de la Meurthe to offer a prize of 50,000 francs for the first heavier-than-air flight around a one kilometre closed circuit.

In 1906 Archdeacon commissioned a propeller-driven motorcycle, the Aéromotocyclette Anzani, which achieved a timed speed of 79.5 kilometres per hour at Achères-la-Forêt.

[18][19] This aéromotocyclette, based on a 'Buchet' motorcycle,[20] was equipped with a 6-horsepower Anzani engine driving a propeller mounted on a 1.5 m (4.9 ft) steel tube.

In November 1905 the Wright Brothers had written a letter to George Besançon, the editor of l'Aérophile describing their recent achievements in detail.

A minority, including Besançon, Ferber and Henry Kapférer, believed the claims of the Wright Brothers, but the majority, led by Archdeacon, thought that they were false.

[17] In August 1908, after Wilbur Wright's demonstrations at Les Hunaudières race course near Le Mans, Archdeacon publicly admitted that he had done them an injustice.

[8] Ernest Archdeacon is widely cited as the first aeroplane passenger in Europe when he was piloted by Henry Farman at Ghent on 29 May 1908.

He wrote "Why I became an Esperanto speaker" (Pourquoi je suis devenu espérantiste, Paris: Fayard, 1910, 265 p.), prefaced by Henri Farman.

He was elected president of the Société Française pour la Propagation de l'Espéranto in 1925, and advocated that international language until the end of his life.