well EHAM went completed going from infra 4 to 5 6 months ago, and I've been watching the cargo numbers and they've stayed the same! 250K potential, 160K actual, 300K supplied by airlines. So no change at all despite the infra increase!

Simon

The circle of catchment area does not actually represent the catchment area, it is just an approximation of it.

The actual catchment area is the set of demand squares (rectangles) that overlap sufficiently with this circle, in and On / Off fashion. Meaning the square is either 100% in or 100% out).

So while the airport expansion may increase the overlap of several demand squares with the circle, but if it does not flip a single square from Off to On, then you will see zero gain from the airport expansion (or from Traffic level change).

We used to be able to see the underlying squares. Looking at the squares would have given you complete answer to a question like this one.

But, some idiot complained about some "unfairness" of the squares, and Sami decided to just hide them.

Unfortunate result is that the complaining idiot may not even be playing the game any more, but all the rest of us are left in the dark because of his question / complaint.