ABSTRACT
The rst rules and regulations governing access at airports became ofcial with the creation of the High Density Rule (HDR) in 1969 in the United States. However, the idea of a slot vis-à-vis airport access appeared three years earlier, in 1966, when airlines agreed to limit their ights at National airport to 40 per hour. The enactment of the HDR measure was seen at the time, as a temporary solution to congestion and delays and thus the idea of a slot in this context was considered provisional. It should also be noted that these decisions were made in the era of economic regulation of airlines in the US. Europe at this time did not face the same degree of airport congestion due to the tight economic regulation of aviation, the need for bilaterals and the dominance of home markets by national carriers.
