A model for enhancing robustness of aircraft and passenger connections

Airlines schedules are often subject to various uncontrollable factors that cause disruptions and delays. These delays not only constitute, for many passengers, the painful part of air travel, but also represent for airlines a significant financial burden. In this paper, we present a model for building robust aircraft routes that are less vulnerable to disruptions through judiciously distributing slacks to connections where they are most needed operationally. Toward this end, the model assigns legs to aircraft and determines the flights departure times, while maintaining the designated time-slot assignments at airports, and satisfying operational constraints. The considered objective function is a newly proposed surrogate measure of robustness that implicitly captures the robustness both pertaining to aircraft and passenger connections. Computational experiments carried out on real-world-based instances, with up to 1278 flights and 251 aircraft, show that the model yields solutions that are remarkably robust. In particular, a simulation study reveals that the total delays, number of delayed flights, and number of missed connections can be significantly reduced. (C) 2013 Elsevier Ltd. All rights reserved.