During the 1930s the need for a municipal aerodrome near Watford was debated at length, but it took almost a decade before the Air Ministry ultimately requisitioned the land at Leavesden for an aircraft factory. Large numbers of Halifaxes and Mosquitoes were subsequently produced there, and these played a vital part in the progress of the Second World War. In peacetime, de Havilland used the factory units for the manufacture of aero engines and the overhaul of its own aircraft. As a result of numerous takeovers and amalgamations, de Havilland eventually became a subsidiary of Rolls-Royce and the latter company continued to build helicopter engines on the site until the factory closed in 1992. From the 1950s, Leavesden also played host to air-taxi and charter companies and even hosted scheduled services for a brief period in the early 1970s. Many people gained their wings with the various flying schools based at the aerodrome, and pleasure flights in airships were a popular attraction. The aerodrome closed soon after Rolls-Royce vacated the site and is now a major film studio, business park and housing estate. Warner Bros’ recent purchase of the site means the company is the only Hollywood studio with a permanent base in the UK. Some original buildings nevertheless survive, including the distinctive control tower. This exhaustively researched history examines in detail the most notable events and personalities associated with Leavesden Aerodrome. It includes several hundred photographs, many of which have not been previously published.