I think air fares are higher anyway but I like Southwest as they have nonstop flights both ways (to/from Nashville) and then there's the free baggage allowance AND the option to cancel and not lose all your money ( you can use it for another flight). You can also keep an eye on it, rebook at a lower fare and "bank" the savings.
Oh, I sound like a commercial! Sorry. Just wanted people to know they had released more dates. Suspect there will be a sale coming up soon? The fares to/from Nashville are 'reasonable' for me at the price they are now. Not great but not bad!