I recently spotted that Zurich Airport’s passenger growth went negative in October 2019.

This was a bit of a shock. I dived into their (public) data and came up with a graph of their growth over the last two years.

I posted it on Facebook, not on the blog. You can see that plot here. Feel free to click on my name and then “Follow” if you want to see future blog posts appear in your Facebook feed (I put a link to each new blog post on Facebook with public access).

It’s now January so two more months’ data is now available. Let’s see what’s happened since October in Zurich (and Paris):

Zurich slipped slightly above 0% growth (vs one year ago) in November (0.7%) and December (1.2%). Still, the nine lowest growth rates of the last two years were in the last ten months.

The story gets interesting when we look at the big picture. Here’s Zurich’s November results:

What’s interesting is the decrease in passenger air traffic movements (take-offs and landings) of 5.9% compared to November 2018. That means around 3% less planes landing and taking off.

[Update: in fact it means 5.9% less planes, not 3%. That’s quite a drop.]

Since passenger numbers are relatively flat compared to a year ago, it means—as we see above—that there are more passengers per flight (an increase on average from 117.6 to 127.6).

As for December:

Same thing. 5% less traffic movements compared to December 2018, so 2.5% less incoming and outgoing flights.

[Update: again, this means 5% less planes, not 2.5%.]

One interesting thing missing from the data is the yearly change in size/weight/age/model of the planes taking-off and landing. For instance, does the 3% drop in take-offs and landings in November correspond to an overall loss in weight and thus fuel and thus CO2 emissions, even when taking into account the increased number of passengers per plane?

My guess is that yes, Zurich Airport is now on a decreasing CO2 emissions path even with basically flat passenger numbers.

This leads to an amusing dilemma. Should Zurich Airport publicize their decreasing CO2 emissions?

As for Paris Airports (CDG and Orly), growth is also hovering around zero (0.9% in November, -0.3% in December), but the fairly epic strikes in France mean that we don’t know what would have happened without them.

Stay tuned!

[Data sources: here, here, and here, Cover photo: Hansueli Krapf]