Available space, weather and air traffic volume are key factors that go into airfield design. Robert Hoxie, who helped redesign Chicago O’Hare’s airfield, explains how runways are mapped out. Photo Illustration: Adele Morgan/The Wall Street Journal

Available space, weather and air traffic volume are key factors that go into airfield design. Robert Hoxie, who helped redesign Chicago O’Hare’s airfield, explains how runways are mapped out. Photo Illustration: Adele Morgan/The Wall Street Journal