This is my best recollection...
Wholly-owned subisideraries of US Airways Group:
US Airways, Inc. (mainline)
Express Carriers:
Allegheny
Piedmont
PSA
Mid Atlantic (formerly Potomac Air during the UAL merger)
(Is the Shuttle still a separate division?)
Mesa Air Group:
Mesa Airlines
Air Midwest
Freedom Airlines (flies as AWA Express, not US Airways yet)
CC Air (acquired by Mesa Air Group in early '90s, shut down by MAG recently, Nov 1 maybe)
Wexford Management:
(Wexford has several airline investments, including several US Airways Express partners)
Chautauqua
Shuttle America
Midway (doesn't Wexford have a hand in Midways BK... Maybe DIP financing? And US Airways group will get a stake in Midway once it emerges from BK...)
Other Express partners include independants Trans States and Colgan Air.
Sometimes, it seems like US Airways has an "Office of Complicating Matters".