During the era in which the Hawker Aircraft company developed the Hurricane, RAF Fighter Command comprised just 13 squadrons, equipped with the Hawker Fury, Hawker Demon, or the Bristol Bulldog, all biplanes furnished with fixed-pitch wooden propellers and non-retractable undercarriages. At the time, there was an institutional reluctance towards change within the Air Staff; according to aviation author Francis K. Mason, some senior figures were prejudiced against the adoption of monoplane fighter aircraft, while mid-level officers were typically approachable on the subject and design concepts that made use of such configurations.