The Narita International Airport is the second-busiest airport in Japan. It is one of the Asian hubs of Delta Airlines, where passengers going to/from the US pass through before proceeding to their destinations in Asia.
I passed through Narita, which serves the greater Tokyo, barely a week after the tsunami hit Japan and the nuclear accident in Fushima happened. Traffic in the airport was uneven: there are less passengers going in (my flight from New York was barely half-full), but flights leaving the airport are full. It seems people are keen on escaping the (rumored) radiation leaks coming from the stricken reactor about a hundred miles away.