Air trav­el is an unnat­ur­al activ­i­ty that has become nor­mal. You’re stuck in a met­al tube with hun­dreds of strangers (and strange smells), defy­ing grav­i­ty and rac­ing through the sky. But oh, the places you’ll go! We vis­it the world’s busiest air­port to see how it all comes togeth­er. (Part 1 of ​“Freako­nom­ics Radio Takes to the Skies.”)