In June 1923, Cargill joined the newly re-named
Princess Mary's Royal Air Force Nursing Service. She was promoted to
sister on 1 July 1926, and to senior sister on 1 February 1939. During the
interwar period, she served in the United Kingdom and in the Middle East. From 1942 to 1944, she served in the United Kingdom and in
Aden. Cargill returned to the United Kingdom after the end of the war and spent the rest of her military career as matron of the RAF Hospital in
Matlock, Derbyshire. On 1 February 1949, when the women's forces were integrated into the
British Armed Forces, she was granted the rank of
air commandant. She was appointed a
Commander of the Order of St John (CStJ) in June 1949, and a
Dame Commander of the Order of the British Empire in the
1951 New Year Honours. Cargill retired from the military due to "medical unfitness for air force service" on 12 May 1952. ==Death==