On the outbreak of the First World War, Travers joined the Royal Naval Air Service (RNAS). His service was eventful. He crashed several times and narrowly failed to shoot down a Zeppelin. He became a squadron commander, and when the RNAS merged with the Royal Flying Corps he transferred to the new Royal Air Force with the rank of Major in 1918. He served in south Russia during the Allied intervention in the Russian Civil War, in 1919, and received the Air Force Cross in 1920.