sentences:  Watson's method of lateral control was applied by him in three different aeroplanes; the first was built in late 1909, the second in July 1910 and his third in 1913.On 16 March 1915, Watson gained his Royal Aero Club Certificate No.1,117 (equivalent of a pilot's licence) with the London and Provincial School at the London Aerodrome, Hendon, having sought a commission with the Royal Naval Air Service with the outbreak of war in 1914.