He began his flying career in the
Royal Naval Air Service in 1917 and until the
armistice served as a pilot in North Sea patrols. The RNAS became the
Royal Air Force at the beginning of April 1918. Following his wartime service he was awarded a permanent commission in the rank of Flying Officer (Aeroplane and Seaplane) in October 1919. After serving in the Mediterranean with
202 and
267 Flying Boat Squadrons he spent three years on flying boat test and experimental duties with
MAEE.
Far East Flight Carnegie joined the Singapore-based
RAF Far East Flight in May 1927 as captain of Supermarine Southampton II flying boat S1150 studying the feasibility of long-distance flights by flying boat to Australia and the Far East, He subsequently remained in Singapore until early 1930, amongst other things helping set up the
Singapore Flying Club.
Calshot In 1930–1931 Carnegie was Officer Commanding the sea plane training squadron at
RAF Calshot on Southampton Water, the United Kingdom's main seaplane/flying boat development and training unit. David Carnegie was able to maintain his involvement with flying boats and sea planes until promoted to headquarters in 1932. ==Air Ministry==