Image by John CARTER for Unsplash

Air Freight Routes are some of the most important structures in modern day logistics. In a single year—as current structures stand—they can move as much as 65.7 million metric tons of cargo hundreds of kilometers across the world. Yet despite their relevance to global trade, little has been written on them and their actual patterns.

This week, we wanted to address this lack of information by diving deep into the actual structures of air freight. More so at a time when air cargo rates have begun a steady rise as the end of the year approaches. Just in the last two months, air cargo rates jumped from an average cost of $3.9 per kilogram of cargo to $4.1 per kilogram—which might not seem as much, but imagine transporting tons of cargo through air. Mostly as a result of expedited shipments ahead of the holiday season—a pattern that has been on the news for weeks now.

So, let’s jump directly into the topic: why is air cargo important?

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Perhaps the most intuitive starting point is to compare air to its closest rival: ocean. Now, while both means of transportation serve the same goal in the abstract—to move products from one point to the other—they actually behave very differently when it comes to strategy. Humanity has become extremely efficient at building container ships capable of transporting thousands of tons of goods per trip, making transportation relatively cheap. Meanwhile, the largest cargo plane ever built, the Antonov An-225 Mriya, could only hold 250,000 kgs at a time. 

Not surprisingly, air cargo is much more expensive than ocean freight. As of the time of writing, the average cost of shipping a 40ft container was $4,775 regardless of its weight. If we consider that the maximum tare weight of a container of such dimensions is 30,400 kilograms, it could cost, on average, $126,058 to send the same cargo by air. So, air cargo will mostly be used for emergencies or expedite shipments—today, for instance, it is likely the result of increased demand ahead of the holiday season or miscalculations that left suppliers understocked.

The same is true when it comes to routes—and here is where we want to spend most of our time today. Some weeks ago, we wrote a white paper on the structure of choke points in ocean trade—the bulk of which were found in South East Asia, and Europe. Now, we want to turn our attention to air freight to better understand how their structure differs from ocean cargo.

To do this, we used data made publicly available by Delft University of Technology. Their data—albeit only covering the year 2019—proves to be the most comprehensive list of publicly available trade routes for air freight. The analysis that follows is based directly on their dataset.

First, thinking in a similar vein to our choke points research, we wanted to look at the most important areas for air freight—namely, air ports. To do this, we examined the amount of times airport names were mentioned amongst key trade routes as either departure or destination points. We counted each and found the ten largest airports by number of air freight routes—shown in the map below. While Asia and Europe do play a crucial role in air cargo traffic, we noticed the emergence of another key region: the Middle East. In fact, Dubai airport has a stunning 1,076 cargo routes, making it the most popular airport for air freight. Also worth noting is that, while on ocean freight, a bulk of cargo is concentrated in the Strait of Malacca in Southeast Asia, when it comes to air cargo, it is actually northeastern airports that carry more weight, such as Incheon in South Korea (994 routes) and Hong Kong (803 routes).

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Now, the data set we are using goes much deeper than listing airports themselves. It actually goes into great detail as to which are the busiest routes across airports. The graph below looks at just the 10 busiest air freight corridors by the amount of cargo transported in a year. Perhaps the most crucial finding is how diversified air freight routes are. While almost all ocean freight traverses through one of 23 choke points at one point or another, the ten busiest air cargo routes account for just 4.92% of cargo transported. The busiest corridor, between Taiwan and Hong Kong, accounted for just 0.84% of air cargo—or some 553,990 tons worth of goods. Yet, again, we notice that the bulk of routes are between Asian air ports, with one notable exception: Anchorage, Alaska. This northern airport serves as a crucial stop for trans pacific trade.

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The prevalence of Anchorage amongst top trade routes is quite telling of a key difference in air freight: the need to make constant stoops to refuel or redistribute shipments to other air crafts. This is a pattern we noticed when splitting air freight routes according to their providers, focusing on the three largest carriers in the world: DHL, UPS, and FedEx.

The map below, for instance, shows the entirety of the DHL air freight network across the world. The thickness of each line represents the tons of cargo carried across each route and, by clicking on the airports displayed, you will be able to see the routes connecting that airport to the rest of the world.

DHL Air Freight Routes by Cargo Transported (2019)

Anchorage, cone more, emerges as a key route to DHL. Similarly, we noticed that a number of smaller US cities served as key hubs to DHL, such as Cincinnati, Houston, and Miami. Again, since air freight needs more stops, these cities—which likely receive little cargo demand—serve as transshipment hubs, much as Singapore serves as a crucial stop in global trade to redistribute cargo.

A similar pattern can be observed when it comes to FedEx. Anchorage, once more, is a crucial transshipment hub, but is challenged by Honolulu, in Hawaii, which serves as yet another crucial trade artery given its location in the middle of the pacific. Within the US, the most important airport seems to be Memphis, followed in a distant second by L.A.

FEDEX Air Freight Routes by Cargo Transported (2019)

Finally, we can do the same exercise for UPS to complete our understanding of air freight. Just like DHL and FedEx, UPS is reliant on Anchorage and Honolulu for trans-pacific trade. And, once more, we see the prevalence of an internal transshipment airport in the form of Louisville, Kentucky. 

UPS Air Freight Routes by Cargo Transported (2019)

So, while ocean freight is reliant on the shapes of seas and some crucial choke points or canals, air cargo has other limitations such as fuel consumption, and long distances. As a result, air freight has developed a number of strategic stops to redistribute packages and send them to their end destination. All this to deliver products with ease even if they need to cross the entire planet.