Integrated Airline Scheduling

Abstract

Two approaches for integrated airline scheduling were presented and evaluated. They integrate the subproblems network design, frequency assignment, flight scheduling, fleet assignment, and aircraft routing. Furthermore, a schedule evaluation procedure was developed and calibrated that is required by both airline scheduling approaches. Both planning approaches are able to represent airline operations and practical requirements on a higher level of detail compared to many solution models presented so far. There are fewer simplifying assumptions or restrictions to certain planning scenarios. Their only requirement is to receive a quality measure for each schedule processed. The first airline scheduling approach follows the traditional sequential planning paradigm. This stepwise approach is realized in an iterative procedure consisting of solution models from literature. In contrast, the second planning approach represents a truly simultaneous model. In a self-adaptive metaheuristic, each processed solution represents a complete airline schedule, thus including all former subproblems implicitly. A comparison in which both approaches are applied to the same scenarios confirmed the postulated higher performance of a simultaneous optimization since the simultaneous approach outperformed the sequential approach with regard to the operating profit of the obtained schedules and the required computational effort. The capability of the simultaneous planning approach is further investigated by its application to scenarios that were modified implying a certain structure of the optimal solutions. For all experiments, the resulting schedules are in accordance with theoretical expectations.