One of the domains of territory is the aerial domain. It includes the air directly above the state's terrestrial and fluvial domains, all the way up to where the outer space begins.
The International Convention on Civil Aviation holds that every state has complete and exclusive sovereignty over the air space above its territory. It also regulates flight of civil aircraft over the territory of another state except by special agreement or otherwise, and in accordance with the terms thereof.
With the development of modern air navigation, it has been suggested as a better rule to allow innocent passage to a certain height in order to provide freedom of transportation.