Optimising aircraft routing and fleet assignment with flight unit loops: a novel decision unit approach for reducing model complexity

Focusing on the optimisation of short-term aircraft routeing and fleet assignment, this study addresses the characteristic of airline operations typically being large-scale nonlinear programming problems. To reduce the model scale, the concepts of “flight unit string” and “flight unit loop” are introduced. Based on these concepts, an integrated optimisation model for aircraft routeing and fleet assignment prioritising flight unit loops is constructed. The model aims to minimise the average delay impact of flights and maximise profit, taking into account the spatio-temporal constraints of flights and daily maintenance requirements. This approach ensures the generation of flight loops and effectively reduces the model scale. Furthermore, a multi-objective optimisation algorithm incorporating greedy strategies, clustering algorithms, and non-dominated sorting genetic algorithms is designed to solve the model. Through experiment analysis, the effectiveness of the model and algorithm is validated, which can provide scientific solutions for airline.