United Airlines

United Airlines operates more than 3,600 flights a day to more than 210 U.S. domestic and international destinations from its hubs in Los Angeles, San Francisco, Denver, Chicago and Washington, D.C. Like all airlines after 9/11, United struggled financially, but continued to focus on operating efficiency throughout this difficult period. In February 2006, United Airlines began a fresh chapter in their evolution as a company and now trades on the NASDAQ as UAUA with over $4 billion in market capitalization.

Combined Through and Fleet Assignment Model

The Combined Through and Fleet Assignment Model (ctFAM), integrates two airline models, the Fleet Assignment Model (FAM) and the Through Assignment Model (TAM), into one single model. We developed a novel very large-scale neighborhood (VLSN) search algorithm that obtained an annual savings of over $25 million compared to the United solution.

Multi-criteria Combined Through and Fleet Assignment Model

Innovative Scheduling often develops tools in phases. This project was an extension of our initial success with United Airlines. In this engagement, we expanded the objective function of our first model to consider multiple criteria. We simultaneously included the crew and manpower resource issues. We developed an approach that either enumerated several pareto-optimal solutions or produced solutions that minimized the weighted sum of multiple objectives.

Combined Through and Fleet Assignment Model with Time Windows

In our third project with United Airlines, we incorporated time windows into the network structure and into the optimization model. We extended our Very Large Scale Network search algorithm and demonstrated that annual savings of over $50 million can be realized by using this improved methodology.