The Blériot XI is a French aircraft from the pioneer era of aviation. The first example was used by Louis Blériot to make the first flight across the English Channel in a heavier-than-air aircraft, on 25 July 1909. This is one of the most famous accomplishments of the pioneer era of aviation, and not only won Blériot a lasting place in history but also assured the future of his aircraft manufacturing business. The event caused a major reappraisal of the importance of aviation; the English newspaper The Daily Express led its story of the flight with the headline "Britain is no longer an Island".

The pioneer era of aviation was the period of aviation history between the first successful powered flight, generally accepted to have been made by the Wright Brothers on 17 December 1903, and the outbreak of the First World War in August 1914.