The National Academies

ACRP 03-40 [Completed]

Air Demand in a Dynamic Competitive Context with the Automobile

  Project Data
Funds: $500,000
Research Agency: Matt Coogan and RSG
Principal Investigator: Matt Coogan
Effective Date: 7/14/2016
Completion Date: 2/13/2019


Airports must contend with a constantly shifting market for air transport services, and this problem is not unique to a particular type or class of airport. Airports that once thrived on feeder flights now find fewer carriers even interested in competing for their local markets. In many cases, the result is a shrinking market, with trips on feeder flights often replaced by auto trips to competing airports. It is clear from recent research that the automobile competes directly with airlines for certain kinds of trips, but relatively little is known about how the choice between airline and automobile travel is made. This is the case both for full trips (auto replaces air for the total trip) and for feeder segments (auto replaces as feeder to more distant airport). Research has been undertaken on the role of rail, for example, as a competitor to air in selected markets (e.g., NCRRP Project 03-02, “Passenger Rail in the Context of Dynamic Travel Markets”), but it is the automobile that is the closest competitor for potential flight patrons, even in the case of very long distance trips where the car is sometimes chosen in spite of major travel time differences. Mode choice decisions are made routinely concerning longer distance trips, with the potential air traveler choosing instead multi-day auto trips—a pattern often referred to as “trip chaining.” Factors such as party size and income interact to make mode selection complicated: a travel party of two may choose air while a travel party of five chooses auto, even for very long distances. A lower income car-owning family may choose to use the car out of necessity, with higher income families having more choices for faster transportation. In the American experience, the auto is often the primary, dominant competitor to air, even for trips of significant length (over 500 miles). In response, a better understanding of the critical factors contributing to mode-choice is needed, both for shorter as well as longer distance travel. There have been many different explanations presented for mode choice behavior based on a range of issues: demographics, security and safety, cost, travel congestion, frequency of service and efficiency, flexibility, consumer perceptions, and others. Understanding how these issues impact mode choice, particularly when comparing airline versus automobile travel, is critical to future policy, marketing, and investment decisions affecting airport infrastructure and services. 


The objective of the research was to develop an analytical framework and a set of application scenarios to help evaluate the role of the automobile as a competitor to the airlines in intercity travel. This research was aimed at helpairports, airlines, and the broader transportation community understand the competitive nature of airline travel versus automobile travel, and how that competition impacts infrastructure priorities. To accomplish this objective, the research should consider (in addition to the more traditional factors of time, cost, and delay) the effects of possible changes in many factors, such as the following:
  • demographics,
  • consumer expectations,
  • technology,
  • institutional policies,
  • safety and security concerns,
  • environmental effects,
  • airline service,
  • travel-time efficiency, and
  • economic conditions.
This research built on past research as well as incorporating new market research about how the intercity traveler makes modal decisions. In addition, this research targeted the practitioner in the field, with relevance to those involved in actual decision making. The product of this research included an evaluation of the analytical framework and a discussion of the relative strengths and weaknesses of the factors considered.

The research plan was divided into two phases:

Phase I

(1) Literature review, including relevant reports from ACRP, NCHRP, and NCRRP that deal with questions of choice between air, auto, and other modes of intercity travel.  The research team also identified other relevant literature concerning the following: (a) consumer and household choice behavior under conditions of uncertainty, (b) effects of emerging technologies on consumer choice, (c) trip chaining, (d) state-of-the-art market research techniques, and (e) other components of social and demographic change impacting mode choice.  (2) Data collection activity. Building on previous work, additional data collection plan was designed and carried out to build a useable database to improve understanding of how decisions between airline and automobile travel are made. This plan included a gap analysis to help focus on what additional data collection procedures are necessary and possible and what is currently not available but desired. The data collection plan that is the output of this task will be reviewed with the panel prior to implementation. Following panel approval, implement the data collection plan to compile, to the extent possible, the required information for analysis. Where possible, open-source data should be made available in the final product as part of the deliverables.  Phase I culminated with an Interim report that presented the conclusions of the literature review and the analytical framework, along with a set of proposed application scenarios. 

Phase II

Test applications demonstrated how the analytical framework developed in Phase I could be applied to test alternative scenarios, including the input of data and the potential output of results. This demonstration also illustrated how the proposed analytical framework could be validated, how concepts of risk and uncertainty should be addressed, and how a range of competitive conditions might impact travel demand and airline versus automobile mode choice in representative travel corridors.  The final products included an executive summary and final report, addressing implications for airport, airlines, and other aviation industry planners, managers and decision makers.  

STATUS: The final report has been released as ACRP Research Report 204.

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