Air travel demand and airline seat inventory management

Abstract

Many airlines practice differential pricing of fare products that share a common inventory of available seats on an aircraft. Seat inventory management is the process of limiting the number of seats made available to each fare class. The objective of both strategies is to maximize the total revenues generated by the mix of fare products sold for a flight. This dissertation first examines the evolution of airline marketing and seat inventory management practices. A demand segmentation model is developed to help explain current airline fare structures. A conceptual model of the consumer choice process for air travel is then presented, and extended to describe the airline reservations process and the probabilistic elements that can affect seat inventory control. A survey of current airline practice in this area revealed that seat inventory control is an ad-hoc process which depends heavily on human judgement. Past work on quantitative approaches has focused on large-scale optimization models that solve simple representations of the problem. A primary objective of this research was the development of a quantitative approach based on the practical constraints faced by airlines. The Expected Marginal Seat Revenue (EMSR) model developed in this thesis is a decision framework for maximizing flight leg revenues which can be applied to multiple nested fare class inventories. It is applied to a dynamic process of booking limit revision for future flight departures, and overbooking factors as well as fare class upgrade probabilities are incorporated. Examples of EMSR model results are presented, and a critical analysis of the demand assumptions and sensitivity of the model is performed. The EMSR model was implemented as part of an automated seat inventory control system at Western Airlines and tested on a sample of actual flights. Compared to flights managed by existing manual methods, flights for which fare class booking limits were set and revised automatically on the basis of the EMSR decision model carried more passengers at a lower yield, and generated higher total revenues.