Thinking about it, I bet you can prove this is the topology. If the graph is generally densely connected (almost all nodes have 3+ destinations) then the diamet

Thinking about it, I bet you can prove this is the topology. If the graph is generally densely connected (almost all nodes have 3+ destinations) then the diameter can't be that high compared to the size of the graph. Proof left to the reader. So either there are chains like described above at the edges, or there's a chain like that separating two parts of the graph (suppose there was only one route connecting the US to Europe, and it stopped in Newfoundland, Keflavik and Shannon). The last possibility is obviously nonsense, though, we know that major airports are densely connected.