Multi-airport Systems
5.2 Basic Concepts and Issues
Definitions
Market dynamics are the central influence on the development of airports in a metropolitan area, asSec. 5.4demonstrates. It is crucial to use a concept of multi-airport systems based on how the customers and users of the system see it. A functional definition that reflects the realities of the market is appropriate.
Thus, for the purposes of airport planners and operators,
a multi-airport system is the set of significant airports that serve commercial transport in a metropolitan region, without regard to ownership or political control of the indi-vidual airports.
This definition involves several important points:
1. It focuses on airports serving commercial transport. It leaves out military bases, such as Andrews Air Force Base near Washington, DC, or Yokota in the Tokyo area. It does not consider airports dedicated to aircraft manufacturing or shows, such as Boeing Field in Seattle and Le Bourget in Paris. It neglects general avi-ation airfields such as Van Nuys in the Los Angeles area. All these facilities are important from the perspective of air traffic control, but they are not factors in the market for the airport/airline services.
2. It refers to a metropolitan region rather than a city. As a practical reality, this re-gion may include several distinct cities. The San Francisco rere-gion from this per-spective includes the cities of San Francisco, Oakland, and San Jose. The airports of these cities all serve, at different times and in different ways, passengers and cargo associated with the San Francisco metropolitan area.2To reflect this real-ity, it is usual to refer to airports in a multi-airport system with a label indicat-ing their metropolitan region: for example, San Francisco/International and San Francisco/Oakland.3
3. With its focus on the market, the definition does not pay attention to who owns the airport. The Paris multi-airport system consists of the two airports owned by the Aéroports de Paris (Paris/de Gaulle and Paris/Orly) plus the other one in the region that people use, Paris/Beauvais.4Similarly, the definition does not pay at-tention to administrative boundaries. The multi-airport system for Boston in the state of Massachusetts includes Boston/Providence in the state of Rhode Island and Boston/Manchester in the state of New Hampshire. These airports are within an hour or less of the Boston suburbs, often closer in terms of travel time than the primary Boston/Logan airport, and serve many customers in the greater Boston metropolitan region.
4. Finally, the definition focuses on significant airports, typically those that serve more than a million passengers a year. This focuses the discussion on facilities that contribute meaningfully to the air transport services of a metropolitan region.
Prevalence
Multi-airport systems constitute a sizable segment of the airport industry. As of 2009, they already catered to over 2 billion total passengers, well over 80 percent of worldwide traffic.
These 70 multi-airport systems worldwide included 160 airports.
Multi-airport systems have been a feature of all metropolitan areas with the most ori-ginating and terminating traffic, without exception and over several decades. This is a re-markable fact. It stresses the strength of market forces to create and maintain multi-airport systems. Table 5.1demonstrates this phenomenon. It presents the primary (or largest) and secondary airports at all cities that are the largest generators of traffic. Notice that, above a specific level of originating traffic, all the metropolitan areas feature a multi-airport sys-tem.
Source: de Neufville database.
TABLE5.1 Metropolitan Regions Generating More Than 15 Million Originations in 2010 The level of originating traffic needed to justify and maintain a second airport has not been constant. It keeps rising, as Sec. 5.4 explains. As of 2010, the minimum level was about 15 million annual originating passengers for the entire metropolitan area, as Table 5.1indicates. This threshold is likely to change over the coming generation.
The emphasis on originating traffic is vital to the understanding of multi-airport systems.
The focus on locally generated traffic excludes transfers. The passengers beginning (and on
return, ending) their trips in the metropolitan area create the pressure for multiple airports for their region. The transfers passing through the region want easy connections to their next flights and clearly prefer to be at a single airport.
Assuming that the number of passengers originating and returning to a region is equal and that either is half the total number of passengers less the transfers, we obtain that
(5.1) This number can be difficult to determine. Many airports and airlines do not release in-formation about the number of their transfer passengers. Thus, the figures for originating traffic in Tables 5.1 to5.3are estimates. This inevitable lack of precision does not affect the overall association of multi-airport systems with the biggest traffic generators.
Many cities with lower levels of originating traffic also have multi-airport systems.
Some of these are developing multi-airport systems (Table 5.2). Other metropolitan areas feature several airports primarily for technical or political reasons (Table 5.3). Technical reasons, for example, led Taiwan to develop a major international airport for its capital, Taipei/Taoyuan, equipped with 3600-m runways capable of handling large transoceanic air-craft. The downtown airport, Taipei/Sung Shan, is popular with local traffic but simply can-not handle long-distance aircraft with its 2550-m runways. Political reasons led the U.S.
Department of Defense to develop Montreal/Plattsburg originally as a base for long-dis-tance bombers.
Source: de Neufville database.
TABLE5.2 Metropolitan Regions almost Generating 15 Million Originations in 2010
Source: de Neufville database.
TABLE5.3 Multi-airport Systems due to Political or Technical Reasons Unequal Size
Airports within a metropolitan multi-airport system characteristically have significantly different levels of traffic. The typical pattern is that a city has a primary airport (with the most traffic) and one or more secondary airports with between 10 and 50 percent of the traffic of the primary airport.Table 5.4indicates relative levels of traffic of the secondary airports, compared to the primary airport in each of the multi-airport systems associated with the cities with the most originating traffic. The secondary airport rarely has as much traffic as the primary airport serving the most passengers.
Source: de Neufville database.
TABLE5.4 Traffic at Secondary Airports Is a Fraction of That at Primary Airports
The primary airports with the most traffic are not necessarily the largest by size. Wash-ington/Dulles has more runways and land than downtown Washington/Reagan, but for the first 20 years of its existence it served only about 20 percent of the traffic of Washington/
Reagan (about 3 million passengers annually, compared to about 14 million). In fact, air-port operators have often built major new airair-ports far away from prospective clients, and these users have preferred to stay with the older primary airport until a major market shift
occurs. For example, traffic at Washington/Dulles only grew significantly once United Air-lines located a transfer hub there. This action completely changed the market for local cus-tomers.
Exceptionally, a secondary airport may have about the same level of traffic as the primary airport. This happens when a secondary airport grows and overtakes a primary air-port as occurred when Paris/de Gaulle grew past Paris/Orly and Washington/Dulles over-took the other regional airports.