Unless you were flying down the 71 freeway at 90mph, Dayton is definitely much closer to Cinci than Columbus

. I've driven to both many times since I've lived out here. Fares are cheaper to Dayton, Columbus, Louisville, and Indianapolis airports (all within 90mins or less of Cinci). Yes, Delta has a mini-hub at Cinci and they know that their only competition is at least an hour away or more, so they jack up the prices. Also, Southwest, AirTran, Jet Blue and Frontier do not fly into Cinci as far as I can tell...so it's a major airline for you or bust. You can get lucky every so often and find a fare cheap enough where it's worth it, but don't count on it.