Compared to the large number of international conferences that end in disagreement, the consistent success of Schedule Coordination Conferences is remarkable. Some of the contributing factors are:
- the need for delegates to return from the Conference to their headquarters with firm schedules
- the tradition of cooperation in negotiations
- the application of recommended procedures and priorities for slot allocation* which are widely accepted as being fair
* Note: The Conferences deal with adjustments to planned schedules to fit in with the slots available at airports. This activity has nothing to do with adjustments to schedules on the day of operation for air traffic flow management. The two types of slot allocation are quite different and unrelated.
The prime objectives in slot allocation are to mimimize (in terms of the airlines as a whole) the economic penalties arising from any necessary schedule adjustments; and to arrive at solutions to problems involving conflicting demands in an atmosphere of cooperation and goodwill.
A basic priority is historical precedence, sometimes called "grandfather rights". (This expression can be misleading, since the system works through social or moral pressure to achieve consensus, and has no means to enforce "rights").
Under historical precedence, a slot request is accepted as receiving priority if the airline operated at the same time the previous year. The appeal of this principle can be understood if one considers that:
- it allows for continuity of service to the public
- it appeals to a worldwide feeling that it is equitable for those who were there before to retain their position
- it provides the degree of stability and continuity needed for planning and long-term investment
- despite some initial adverse reactions, newcomers also get to appreciate it. Thus, the child becomes a grandfather in one year. No alternative system of precedence has so far been proposed which would gain such wide acceptance.