Not sure if this has really been discussed, but since it's a press release it sounds very official:
http://www.msnbc.msn.com/id/5014430/
My guess is
PIT, which would (assuming the demise of US in some form) be begging for a carrier, as well as providing a great airport facility to launch connections through (much like
BWI is for
WN today). If US pulls out of
PIT, it would be left as basically the largest city in the nation without either a hub-carrier, or large competition (in the case of
MCO).
Other possibilities maybe:
CLT
DAY
LEX
MSP
DIA
MEM
Long shots:
LGA
DCA/
IAD
ATL
CVG