Originally Posted by ATOBTTR

OP if you can fly out of Burbank, there is an option on Frontier that departs BUR at 8:33 PM, connects in LAS and arrives at CVG at 7:05 AM. Similar option on Frontier out of SNA, departing at 8:07 PM and connecting to the same LAS-CVG redeye, arriving at 7:05 AM. Not sure what would be more preferable - a direct to IND with a very tight window to drive to Cincinnati or a connection to CVG that leaves ~1 hour to get off the plane and get where you're going in the Cincinnati area. Landing in CVG also means not having to do an ~2 hr drive after getting off a redeye.

Third option would be, as jrl767 noted which would be booking DL on two separate tickets on LAX-LAS and then LAS-CVG, which arrives at 5:22 AM, with 44 min in LAS. Some risk here. Sub-option 3B would be booking LAX-LAS on any of the numerous carriers that operate LAX-LAS then booking LAS-CVG on DL. B6 has a departure right at 8:00 PM and AA has a departure at 8:15 PM (I didn't check WN).