The Miles M.68 Boxcar, flown on 22 August 1947, had four 75kW Blackburn Cirrus Minor II engines and was basically of Aerovan layout, except that the centre section of the fuselage was designed to mount a detachable container 1.37m square and 3.05m long, the idea being that freight containers could be pre-loaded and the aircraft could be flown with or without the container attached.