If you’ve ever looked at a departures board and seen hundreds of flights listed, you might have wondered which airport is actually the busiest in North America. Airports, just like airlines, compete fiercely to be the largest, the most connected, and the most efficient. But the answer isn’t as simple as naming one airport, because “busiest” can mean different things. It can mean the most flights, the most seats offered, or the most passengers moving through the terminals. And when you look at those different metrics, two airports rise clearly to the top.

So in this video, we take a look at which airport is the busiest in North America, comparing Chicago O’Hare and Atlanta Hartsfield-Jackson, and exploring how route networks, airline hubs, and infrastructure all shape their massive operations.