Who's Hauling Mass: Chicago

According to the latest traffic statistics from the U.S. Department of Transportation, over six million passengers traveled through Chicago's two airports -- O'Hare and Midway -- in the month of February (2007).

United, American (including their express affiliates), and Southwest, the city's three largest carriers, handled 5 million of those passengers, and together they combined for roughly 75% of the total traffic in and out of Chicago.