The flipside to all of this (outside of the suggestion that CLT has PIT's O&D, although it might without the monopoloy hub pricing that US still employs) is that PHL is still a crappy hub and CLT lacks O&D.
US connects far too much traffic at PHL, which will ultimately kill the franchise in the Northeast--nobody who wants to get where they are going connects in PHL. CLT will never have high O&D as long as US continues to price gouge in the CLT market.
Nothing is going to change this.
As an aside, I love the PHL lovers on here:
Two years ago: "WN and B6 will never enter PIT."
Now: "Well, they have not added flights."
Both are wrong, the second in a particularly ironic way.
B6 flies what, 4x/day to NYC and BOS--markets that already have AA, DL, US, CO (NYC) and US in the BOS case. WN's frequency additions have come directly at US expense--since service inception in PIT, they've added PHX, MDW, and PHL frequencies. What does that say about US' ability to defened it's turf?