Improving slot allocation at Level 3 airports

Abstract

Most of the busiest airports outside the United States, including the major connecting hubs, are classified as Level 3. At these airports, airlines need to be assigned slots by a schedule coordinator to schedule flights. Slot allocation is driven by a set of rules and priorities specified in the Worldwide Slot Guidelines (WSG) published by the International Air Transport Association (IATA). The process and rules for slot allocation at Level 3 airports carry enormous economic and regulatory implications for the global air transport sector. The objective of this paper is to contribute to the ongoing quest for improvements to the process that can be realistically implemented in practice. For that purpose, we have developed an optimization model, fully compliant with the WSG, for allocating airport slots to airlines and applied it at a few airports of varying sizes in Portugal, in order to compare the slot allocations performed by the coordinators with the best possible slot allocations under a variety of objectives and constraints, as well as to assess the impacts of potential changes to the WSG. The results obtained show that some even limited changes to the WSG can, on their own, bring considerable benefits in the short term to the slot allocation process. We have also identified and summarized a number of other potential changes to the WSG, with potential to make the slot allocation process even more efficient, fair, transparent and inclusive.