Wiredautopia, “airtraffc”, December 7, 2008, http://www.youtube.com/watch?feature=player_embedded&v=oR00_uLfGVE

Research and Innovative Technology Administration, “Table 1–46: Air Passenger Travel Departures from the United States to Selected Foreign Countries by Flag of Carriers”, in National Transportation Statistics, U. S. Dept. of Transportation, July 2010, http://www.bts.gov/publications/national_transportation_statistics/html/table_01_46.html