Merging the Aerotropolis concept with the ’15-minute city’ – part one: understanding the notions


Two concepts that were unheard of a decade ago but which have both impacted - or will soon do so - on human interaction are the aerotropolis (the economic development of a region around an airport, the growth of which is determined by that airport) and the 15-minute City, or 15mC.

The former is a catalyst to economic growth, while the latter aims to 'kettle' that growth and the associated interactions within a small, walk-able area, principally on economic (or pseudo-economic, depending how you look at it) grounds. While the former supports and enhances the human desire to travel by supplying the air routes that the economy demands, the latter throttles it by herding people into small townships.

Can there be an accommodation between these two philosophies?

A project to develop a 15mC close to Linate Airport in Milan will be an indicator of the likelihood of that happening, while a much bigger challenge awaits at the giant NEOM and 'The Line' complexes in Saudi Arabia.

This is part one of a two-part report.

  • The concepts of the airport city and of the aerotropolis are long established, the latter having followed on from the seaport, railway network and highway system.
  • They have all acted as economic drivers that have served to enhance business opportunities at national, legal and global levels.
  • The latest incarnation of thinking, since 2015, is the 15-minute City (15mC), which seeks to concentrate as many human and commercial interactions as possible in one small, local area that people rarely leave.

The airport has taken on the same role as seaports, railroads and highways before it - as an economic driver

The concept of the Airport City and the Aerotropolis - the surrounding area whose economic function is dictated by the operations at the airport - was first imagined several decades ago and subsequently catalogued and described by the American academic John Kasarda from 2000 onwards, based on his prior research on airport-driven economic development.

The theory is quite a simple one, according to Professor Kasarda.

Airports have evolved as drivers of business location and urban development in the 21st century in the same way as highways did in the 20th century, railroads in the 19th century, and seaports in the 18th century.

The engine of the aerotropolis is the airport and its air routes, which offer firms rapid connectivity. In the aerotropolis model, the time and cost of connectivity replace space and distance as the primary metrics shaping development, with 'economies of speed' becoming as salient for the competitiveness of firms and places as economies of scale and scope. In this model, it is not how far, but how fast, widely separated firms and places can connect.

The aerotropolis encompasses aviation-dependent businesses and the commercial services that support them and the multitude of air travellers who pass through the airport annually.

These businesses include, among others, high-tech and advanced manufacturing, logistics, and e-commerce fulfilment; high-value perishables and biomeds; destination retail, sports, entertainment, and medical/wellness complexes; hotels; conference, trade, and exhibition centres; and offices for businesspeople who travel frequently by air or engage in global commerce.

Business parks, logistics parks, R&D parks, time-critical distribution centres, and information technology complexes, as well as hotel, conference, and entertainment venues, are most frequently visible around major new airports on metropolitan peripheries where there is sufficient land, and along the transportation corridors radiating from them.

As increasing numbers of aviation-oriented firms and commercial service providers cluster around and outward from airports, the aerotropolis has become a major urban destination where air travellers and locals alike work, shop, meet, exchange knowledge, conduct business, eat, sleep, and are entertained - often without going more than 15 minutes from the airport.

The outcome is a new form of transit-oriented development centred on runways and along their connecting surface transportation arteries.

Over 80 airport cities and aerotropolises identified worldwide

As of 2017, Professor Kasarda had identified 84 airport cities or aerotropolises worldwide, either operational or under development, although no update on that number has ever been offered, as far as it is known.

Airport cities and Aerotropolis locations, worldwide

The aerotropolis must be a living space too

The aerotropolis is more than clusters and corridors of airport-linked commercial, industrial, and logistics facilities. It also consists of living urban places that must be planned and designed as appealing environmental and social realms.

Some aerotropolises have arisen spontaneously, responding to organic market forces with a lack of planning and contributing to sprawl, while creating highway congestion, pollution, and other negative externalities.

Applying principles of smart urban growth and sustainability are essential to the formation of a successful aerotropolis, as is stakeholder alignment.

Governance entities aligning airport management, airport-surrounding communities, and city and regional officials with local business and economic development leaders should implement aerotropolis planning to achieve greater economic efficiencies along with more attractive and sustainable development, according to Professor Kasarda.

In 2011 Time magazine declared the aerotropolis to be "one of the 10 ideas that will change the world."

The 15-minute City seeks to keep its inhabitants in one place for all its needs, and runs contrary to the ideology behind the airport

There is another concept of urban living that has arisen more recently: namely, the 15-minute City or 15mC, which encourages and enables residents to access most daily amenities within a 15 to 20-minute walk, bike or other mode of transportation from any point in a city, town or village, regardless of size.

There is also a degree of enforcement in town planning where citizens are penalised, usually financially, for vehicular movement outside their own 15mC. For example, by the charging of rates applied to private vehicle usage, which has stimulated widespread public resistance (both lawful and unlawful).

There are arguments for and against the 15mC, but it is not the purpose of this report to air those arguments.

The 15mC is not a new idea, indeed, much of Paris was long built around it and arguably parts of London too. But it has come to prominence in the past five years or so with the support of such organisations as the World Economic Forum, fundamentally on 'environmental' grounds'. The C40 Cities Climate Leadership Group (a mantra of which is to restrict individuals to one leisure air journey every three years) published a framework for cities to "build back better" (a United Nations programme since 2015, but better known as an American expression attributed to the Biden administration) using the 15-minute concept, referring specifically to plans implemented in Milan, Madrid, Edinburgh, and Seattle after COVID-19 outbreaks.

Their report highlights the importance of inclusive community engagement through mechanisms like participatory budgeting and adjusting city plans and infrastructure to encourage dense, complete, overall communities.

'Reorganisation of mobility' is a key element of the 15mC

A manifesto published in Barcelona in Apr-2020 proposed radical change in the organisation of cities in the wake of COVID-19, and was signed by 160 academics and 300 architects.

The proposal has four key elements: reorganisation of mobility, (re)naturalisation of the city, de-commodification of housing, and de-growth.

There is one key element to that proposal which specifically impacts on the air transport business: namely, 'reorganisation of mobility,' because that is exactly what the airport business has been doing with the appearance of the airport city and then the aerotropolis.

The other interesting part of the C40 statement is the reference to "plans implemented in Milan", a city which will be a focus of the second part of this report.

In part two of this report CAPA - Centre for Aviation will consider: the announcement from the Milan airports' operator that it plans to transform a district at Linate Airport into an 'innovative, smart' one with an existing artificial lake and light rail line at the heart of the scheme; Milan's wider Urban Renaissance programme; how the concepts of the Airport City and the 15mC are merging; how, if demand for travel is minimised by over-centralisation and a reduced desire to travel, the need for airports could be reduced accordingly; and how much larger projects - such as those planned in Saudi Arabia - will be a better indicator of the prospects for the Aerotropolis/15mC liaison.

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