That’s the problem with airports these days, as this article shows pretty clearly with some frightening real world examples:
We don’t fly much (my very first flight was only a few years ago) so this is all fairly academic to me. But the basic problems of efficiency and capacity are the same in any complex system, whether it’s a computer network, a database, or an airport. In this case, airports have gotten busier and busier. Expanding airports is expensive and politically difficult, and sometimes geographically impossible. Building new airports is even worse. So existing airports are used at overcapacity in order to compensate. It’s amazing that the system works as well as it does, honestly.