Charles joined his brother in 1906 and the Appareils d'Aviation Les Frères Voisin ("Voisin Brothers' Flying Machines") was formed. Their first successful plane was built in 1907. This machine, a pusher biplane powered by an Antoinette engine, was built for Leon Delagrange and was tested by Charles in February–April before being handed over to him. The first powered flight was made on 16 March 1907, when Charles flew for 10 metres at Neuilly-Bagatelle.
Voisins' aircraft became a significant advance in the aviation history. Record breaking flier Henri Farman flew a Voisin pusher biplane in most of his early flights, notably so when he became first in Europe to successfully complete a 1 km closed circuit at Issy-les-Moulineaux on January 13, 1908. Charles Voisin was present on the ground during this historic flight.