He later became associated with
Louis Blériot, and handled the logistics for Blériot for his cross channel flight of July 25, 1909. He then became the first person to buy a copy of Blériot's aircraft, and also the first pupil at the flying schools which Blériot established, becoming the second person to qualify for an AeCF pilots license through a flight test. (The first licenses were given to prominent aviators without any formal test) He later became one of the chief instructors, and also made proving flights of newly produced Blériot aircraft. He was placed second in the 1909
Gordon Bennett Cup for balloons. In August 1910, flying a Gnome-engined Blériot XI, he won the ''
Circuit de l'Est'', covering the in 12hr 1 min 1 sec, an average speed of Leblanc was first in the race and
Émile Aubrun finished second. The race finished at
Issy-les-Moulineaux, and 200,000 spectators were gathered to see the finish. In November 1910, he represented France in the
Gordon Bennett Trophy race for airplanes, held in New York, but misjudged a turn on his last lap, and crashed: had he not done so, he would have won the competition, which was won by
Claude Grahame-White, also flying a Blériot. During the first World War, he was the general manager of the Blériot factory at Suresnes. In 1919, he was appointed manager of the
Compagnie des Messageries Aeriennes, an airline formed by the major French aircraft manufacturers in order to create a civil aviation market, and he was also put in charge of the Societe des Stocks, which was formed to dispose of the large number of surplus aircraft and aero-engines resulting from the end of the First World War. He died 22 November 1921. ==Awards==