This thesis initially sets out to examine the context of the purchase of two aircraft, on the authority of Michael Collins and funded by the second Dail, during the Treaty negotiations of 1921. The subsequent development of civil aviation policy including the regulation of civil aviation, the management of a civil aerodrome and the possible start of a state sponsored civil air service to Britain or elsewhere is also explained. Michael Collins’ leading role in the establishment of a small Military Air Service in 1922 and the role of that service in the early weeks of the Civil War are examined in detail. The modest expansion in the resources and role of the Air Service following Collins’ death is examined in the context of antipathy toward the ex-RAF pilots and the general indifference of the new Army leadership to military aviation. The survival of military aviation - the Army Air Corps - will be examined in the context of the parsimony of Finance, and the administrative traumas of demobilisation, the Anny mutiny and reorganisation processes of 1923/24. The manner in which the Army leadership exercised command over, and directed aviation policy and professional standards affecting career pilots is examined in the contexts of the contrasting preparations for war of the Army and the Government. The Air Corps’ active roles during the Emergency are assessed against the background of inadequate preparation, insufficient and inappropriate aircraft and improbable tasking by GHQ. Secondary roles in support of the RAF war effort are also elucidated. The Army’s investigation, into the inadequacies of the Air Corps, is examined against the background of the command exercised by an inexpert and disciplinarian officer. The investigation itself is assessed in order to highlight any the bias or prejudice that may have pertained.