I used to do SBN to SDF via CVG. 25-30 minutes from SBN to CVG, and then 16 minutes +/- CVG to SDF. Versus about a 5-hour drive. Total travel time to fly is about 3 hours including getting to the airport about an hour early.

I always chose to fly because I didn't have to do the driving. Oh, and going through Kokomo is a major B.