The earliest and fundamental premise of aero-nationalism was the protection of national security. The protection of national security worked to justify airline nationality. This had two aspects. The first concerned preventing potentially hostile states from entering national airspace. The second aspect of national security as a justification for airline nationality concerned the possibility of making military or other strategic use of civilian aircraft, in particular the deployment of such aircraft for civil defence or emergency needs. An important premise of aviation policy is an answer to the question of whether the airline industry is a commercial, competitive, economic activity or a public utility with a tendency towards natural monopoly. In its early days, the airline sector was commonly treated as a public utility which should serve the national economy or even help to fulfil certain political goals. The autonomous role of airlines as businesses and a source of profit was almost non-existent.