ABSTRACT

NATIONAL AIRSPACE The invention of the balloon and more especially the airplane made it necessary to clarify the rights of states in the air above their territory. As with any newly emerging area of concern, writers advanced a number of theories: (1) states had complete freedom in airspace, just as on the high seas; (2) states could claim territorial jurisdiction in airspace up to about 1,000 feet above the ground, with the upper air again free, as in the case of the high seas; (3) states could claim the entire airspace above a state with no upper limit, but only with a servitude of innocent passage granted to all aircraft registered in friendly foreign countries; and (4) states had absolute and unlimited sovereignty over national airspace, with no upper limit. 1

The last proposition quickly received general approval when the outbreak of World War I led all belligerent states to assert full sovereignty over their national airspace. Neutrals, in turn, denied all right of passage to belligerent aircraft, thus aligning national airspace with the rules applying to the land surface rather than with those applicable to neutral territorial waters. In fact, both the Swiss and the Dutch armed forces, maintaining the integrity of their neutral airspaces, brought down a number of belligerent aircraft that had penetrated their national airspaces. By the end of the conflict, national sovereignty over airspace had gained almost universal acceptance. The 1919 Paris Convention for the Regulation of Aerial Navigation 2 embodied the idea of full sovereignty (Article I) but also contained a right of innocent passage for private aircraft subject to the rules of the convention.