Most large regional cities have their own airports. Is that because growing regions are more likely to open an airport, or because having an airport leads to faster population growth for small regions? Probably, it is a combination of both, but empirically they are difficult to disentangle. However, this 2025 article by Jørn Rattsø (Norwegian University of Science and Technology) and Nicholas Sheard (Deakin University), published in the Journal of Economic Geography (open access) attempts to answer the question of how much regional airports contribute to growth.
Rattsø and Sheard focus on the example of Norway, where the number of regional airports grew rapidly from the 1950s, with fifty new airports opening between 1950 and 2019. They apply an event study difference-in-differences approach with synthetic controls. That means that they compare regions where an airport opened with synthetic controls made up of a weighted average of other regions, between the time before and the time after the opening of the airport. The outcome variable they concentrate on is the regional population, but they also look at employment (in total and by broad industry category).
Rattsø and Sheard find that:
...regions where airports were opened subsequently experienced growth in both population and employment, relative to otherwise similar regions that had been on similar growth paths before the airports were opened...
The size of the effect is relatively modest, with population growth about 0.4 percent higher after 1-5 years, 0.9 percent highers after 6-10 years, 0.5 percent higher after 11-15 years, and no difference after 16-20 years of the airport opening. Rattsø and Sheard also report a number of heterogeneity analyses, which are interesting too:
The population growth effects of new airports are largest and most significant for airports established in the first decade studied (the 1950s) and for new airports opened where there were no other airports within 100km... the growth effects are relatively large and more often statistically significant for airports that are physically larger (measured by length of runway) and that have a connection to at least one of the four largest cities in the country.
The first of those heterogeneity results points to a potential problem with the analysis. Airports are not opened randomly. Governments are more likely to open airports in regions where those airports are likely to have the largest effects first. And so, the effects being largest for the airports that were opened in the 1950s may be because those regions were going to grow rapidly regardless of whether an airport was located there or not. The synthetic control method attempts to deal with this by comparing regions with an airport with a weighted average of other regions without an airport, where the weighted average control 'looks like' the region that received an airport. However, this approach can only ever provide an imperfect control, because the reality is that the regions that are part of the control did not receive an airport, and if airports are allocated first to regions that are likely to grow faster, then the comparison with the synthetic control may simply pick up that fact.
The other heterogeneity results are consistent with what we would expect if regional airports do lead to faster population growth. If airports increase growth, then larger airports should increase growth by more. And connectivity matters, particularly to larger regions (although it is worth noting that when you have an airport, the flights go in both directions, and so it is by no means a given that increasing connectivity leads to net in-migration). The results for employment are also consistent with expectations, with increases in employment in the 'transport and communications' sector, as well as services.
Rattsø and Sheard rightly conclude that:
...the effects were concentrated in the early era of expansion when the air network was much less developed and similar benefits are not likely to be available today. In addition, the effects of having a small airport are limited: having an airport with little air traffic and few connections is not helpful for regional development. For peripheral regions, it may be better to improve road and other infrastructure to reduce travel times to larger airports with better connections, rather than building their own airports.
None of those conclusions should be surprising. However, the results from this study should caution against small regions in modern times arguing strongly for the opening of a new airport. Taking the results from this study at face value, where the air network is already extensive, adding an additional small airport will have little effect on population growth. There may be other good reasons to open a small regional airport, but expecting an increase in population growth should not be among them.
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