Guyancourt Airport

The primary reason for the airport's closure was extensive urban expansion. The land was expropriated for the development of the 'new town' (ville nouvelle) of Saint-Quentin-en-Yvelines. The specific and final project that sealed its fate was the construction of the Renault Technocentre, a massive automotive research and development facility that required the large, flat area occupied by the airfield. Growing noise complaints from the expanding suburban population also contributed to the decision to close it.

The site of the former airport has been completely redeveloped and is unrecognizable as an airfield. The vast majority of the land is now occupied by the **Technocentre Renault**, one of the world's largest automotive R&D centers, which opened in 1998. The remaining parts of the former airfield have been transformed into residential neighborhoods (including one named 'Quartier de l'Aérodrome'), commercial zones, roads, and public green spaces, such as the Parc des Sources de la Bièvre. Some street names in the area, like 'Rue Hélène Boucher' and 'Avenue des Frères Caudron', pay homage to its aviation past.

Guyancourt Airport had a rich and significant history in French aviation.

- **Origins and Golden Age:** While used for aviation as early as 1913, its importance surged in the 1930s when it was acquired by Louis Renault and became the main base for the Caudron-Renault aircraft company. It served as a flight school, a test center for new aircraft, and a manufacturing site.

- **Record-Breaking Hub:** It was the home base for celebrated aviators, most notably Hélène Boucher, who set multiple world speed records in 1934 flying a Caudron C.450 Rafale from Guyancourt before her fatal accident at the airfield the same year.

- **Key Aircraft:** The airport was central to the development and testing of famous Caudron aircraft, including the Caudron Simoun (a popular mail and transport plane used by Air Bleu and the French Air Force) and the high-performance Caudron C.460 Rafale racing plane.

- **World War II:** During the war, the airfield was seized and used by the German Luftwaffe. After the liberation of Paris in 1944, it was repaired and used by the United States Army Air Forces as a transport and liaison airfield, designated Advanced Landing Ground Y-13.

- **Post-War Era:** After the war, it returned to civilian use and became a major hub for general aviation and numerous aero clubs in the Paris region until its closure.

None. There are absolutely no plans or prospects for reopening the airport. The site is fully and permanently occupied by critical infrastructure, including the massive Renault Technocentre, dense residential housing, and commercial buildings. The land has been irreversibly transformed, making any return to aviation activities physically and economically impossible.