Gilbert was born in 1889 in Riom, France. He became interested in flight in his teens and actually built his own version of a flying machine around 1909. The machine appears to have been unsuccessful but Gilbert took on more conventional fixed-wing flying machines, gaining his pilot's license on 4 Oct 1910. By 1911, he was flying a Bleriot XI. In the 1911 Paris to Madrid air race, Gilbert flew across the Pyrenees Mountains and was attacked by an angry mother eagle defending her young and nest; to ward off the large bird, he simply fired pistol shots at her rather than kill her. On 24 April 1913, Gilbert made a record nonstop cross-country flight of 826 km (523 miles) from Villacoublay, France, to Vitoria-Gasteiz, Spain, in 8 hours 23 minutes.