The main hubs are Pittsburgh, Philadelphia & Charlotte. I think your connection would be Charlotte NC, not Charleston. I live in Pittsburgh and they control about 85% of our flights, they are our regions biggest employer. I flew twice into Minneapolis in the early 90's on business trips, at that time they only had 1 gate at MSP.
My husband flies weekly on USAir out of Philadelphia (business). We take nothing but USAir when the 4 of us travel on vacation. The airport in Pittsburgh is beautiful and as Debbie said is a major hub for USAirways (we lived in Pittsburgh for 2 years). I won't hesitate, especially if you are getting a great rate! I checked yesterday on USAirways web site and they are offering some great rates to Orlando (MCO) out of Philly for $165 in August. That's the lowest I have seen it out of PHL on a non stop flight to Orlando. But remember, these low rates on the web site are not usually refundable.
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