True, CLT is just a hub, with less O&D traffic than other cities, but don't discount its geography. People living in Texas flying to Florida (South America, etc.) won't fly up to PHL to connect south. Likewise, people flying between Boston and Chicago would rather connect in PHL than CLT. Focusing your entire operation out of one hub can isolate entire regions of the country. While Continental genrally hubbed in IAH and EWR - both great O&D cities, as a resident of Florida, I rarely could fly them - as I wouldn't connect in EWR to go to MEM, for example. O&D traffic is a huge benefit to airlines' bottoms lines (especially since the fares tend to be higher on direct versus connecting flights) but connecting passengers do generate a lot of revenue. I hope the bean counters at US understand this and maintain and grow their presence in CLT.