The airport actually in Lexington is pretty well served by Delta and some other smaller airlines, and is fairly easily reached from most metropolitan areas. Your next best choice is Cincinnati, which is a major Delta hub. It's about a 2 hour drive from Cincinnati to Lexington, so plan on renting a car if you go that route.
Taxi fares from the airport to campus or the local hotels are (on average) $25-$30.
If you live inside 2-3 hours drive (or just want a great road trip), consider driving to Lexington. It's a beautiful drive, and the weather should be terrific this time of the year. In years past, it's been a great opportunity for attendees who own motorcycles to take a road trip.
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