in january 1930 lees joined the raaf as a cadet at point cook, victoria and in january 1931 took up a short-service commission in the raf. he was made officer commanding no. 72 squadron in 1938 and served in the second world war taking part in the battle of britain in 1940. during the war he served as station commander at raf coltishall, as senior air staff officer at headquarters no. 242 group and then on the sicily invasion force.