The world's main hub airports

THIS week’s briefing on Heathrow examines the merits of hub airports—those at which a lot of incoming passengers transfer to planes bound for airports that are not served directly from their original point of departure. Hubs are popular with airlines because they make their operations considerably more efficient. Airport owners like them because hubs have more flights. And local users like them because they serve more destinations: pooling passengers from many different points of departure makes it possible for airlines to offer flights to places that would otherwise be uneconomic. Heathrow is one of Europe’s main hubs, together with Frankfurt, Charles de Gaulle and Schiphol. But where Heathrow has two runways working flat out, Charles de Gaulle and Frankfurt have four and Schiphol has six. This makes it easier for them to clear backlogs, while a smattering of snow can cause chaos at Heathrow as problems pile up. Read The Economist’s solution to London's lack of airport capacity here.