The Surprising Math Behind Airports and City Size

Earlier this week, I looked at the role of airports in the economic development of cities and regions. Today, I turn to a fairly obvious question whose answer is less obvious: is city and metro size a function of airport size? The short answer is “yes,” but the relationship is not one to one—and the mathematics of that relationship has wider implications.

In general, the bigger the city the more airport activities there are, however they are measured. Metro size is strongly correlated with the total number of flights (.56) and the number of passengers (.59), but less so with total cargo (.24). This makes sense, as cargo hubs are often sited in locations that are equidistant from a number of different markets, rather than at the center of one major one.