Watch on Soap2day. 'En Dirigeable sur les champs de bataille' is a 78-minute film recently discovered in the archives of the French army in Paris. The pilot was Jacques Trolley de Prévaux. His cameraman was Lucien Lesaint. In August and September 1919 they filmed the remains of the Western front, from Nieuwpoort, on the North Sea in Belgium, to the Swiss Alps.