Foursquare has released a map showing travel via plane, train, and automobile covering the heavy travel season between October and December of 2010. Airplane travel crisscrosses the entire country with a blur of lines most densely concentrated around major cities. Travel by train seems to be concentrated mostly in a few areas of the country, most notably in sections along the West Coast, the Chicago area, and the East Coast (New York, Boston, Washington D.C. areas). The data is gathered from Foursquare checkins but doesn’t show the volume of travelers within the actual map itself, only the routes of travel.
The bottom of the map contains a timeline showing the ups and downs of travel traffic for the three modes of transportation. Flying by airplane has the most pronounced changes in travel traffic with the highest spikes just before and after the Thanksgiving and Christmas holidays. Travel by train and car seems to have consistent dips and rises with what seems to be an increase on the weekends and lulls during the weekdays.