An integrated approach to flight scheduling and fleet assignment

This study proposes an integrated approach for optimizing the profit of a multi-route airline network by simultaneously assigning aircraft types to flights and scheduling flight departure times. The proposed integrated model, which allows variability in flight departure times, resolves trade-offs between efficient fleet operation and service quality.; Most recent research in this area has been on fleet assignment models with time windows. Noticeable weaknesses of these are their requirements that flight departure times be limited within small time windows and their assumption that changes of departure time do not affect demand and hence revenues for those flights. No previous model has been found that considers demand and service quality in multiple route flight scheduling.; In this research, the models are developed gradually, from single-route to multiple-route, from individual models to integrated models, and from Mixed Integer Linear Programming to Mixed Integer Non-Linear Programming.; A Non-Linear Programming fleet assignment model with variable departure times is constructed to provide full flexibility in optimizing departure times. Its results are compared with the basic Linear Programming fleet assignment model. The NLP model becomes a component of the proposed integrated models. The integrated models (cost minimization and profit maximization) are formulated and designed to include demand and service quality considerations in multi-route flight scheduling.; An integer relaxation model is tested for lower bound solutions and compared to the NLP mixed integer model. The comparison results show that the total cost objective function of the Mixed Integer model is 11% higher than the lower bound solution. The sensitivity analyses are conducted by varying input parameters over a wide range. The results show that the models are very good at optimizing and that trends in their output are reasonable.; This study demonstrates that the proposed integrated approach is a promising substitute for the existing sequential approaches in the airline scheduling processes.