It\u2019s an unnatural activity that has become normal. You\u2019re stuck in a metal tube with hundreds of strangers (and strange smells), defying gravity and racing through the sky. But oh, the places you\u2019ll go! We visit the world\u2019s busiest airport to see how it all comes together. (Part 1 of \u201cFreakonomics Radio Takes to the Skies.\u201d)