The Besson MB.35 "Passe Partout" was a French two-seat spotter and observation floatplane, designed by Besson. It was intended to serve on "Surcouf" a very large (for its day) submarine, stowed in a sealed hangar. The first aircraft was destroyed during trials and the second was converted to the MB.41, prototype of the Besson MB.411, which did serve on "Surcouf".