Codeshare agreements in the integrated aircraft routing problem

Codesharing, a common form of airline alliances, allows an airline company to market a flight operated by another airline company as its own and thus expand its outreach network. However, for an airline company, some decisions related to codeshare agreements cannot be standalone decisions that do not interact with the airline's flight operation planning decisions including flight scheduling, fleet assignment, aircraft routing and crew scheduling decisions. To the extent of our knowledge, this is the first work in the literature to introduce the idea of codeshare agreements while integrating it with flight scheduling, fleet assignment and aircraft routing while considering propagated delay, deadhead flights and demand uncertainty in an optimization framework. To achieve this, a two-stage stochastic model that integrates flight scheduling, fleet assignment and aircraft routing was developed. Two column generation-based algorithms were developed to solve this highly complex problem and a sensitivity analysis is performed on some parameters. The results show that codeshare agreements can have a significant impact on the profits of an airline company by allowing for more flights to be scheduled while minimizing delay in aircraft routes.