It's all about a series of uphill runways, running in all directions.
Planes stop quicker when landing, then they can free-wheel from the top of the runway downhill to the terminal, which would be located half way down the taxiway that's parallel to the runway. Then, when departing, they can freewheel down the rest of the hill to the bottom of the runway.
OK, so they have to take off uphill, but seeing as they're going up anyway...