According to a Brookings Institute study, people are traveling less since September 2008.
Most US travel is concentrated around 26 hubs.
Half of the flights are less than 500 miles.
Expect delays in metropolitan centers of air travel.
The replacement for radar, the Next Generation Air Transportation System will not be operable until between 2012 to 2018.
There are worse than average delays in New York, Chicago, Philadelphia, Miami, Atlanta, and San Francisco.
http://www.brookings.edu/~/media/Files/rc/reports/2009/1008_air_travel_tomer_puentes/1008_air_travel_report.pdf
