We are booked for Disney August 19th-27th and were also going to drive. We usually fly out of Detroit and found the prices way higher than in past years. I just booked this morning for less than $230 a person out of flint. On top of that I noticed parking is way way cheaper than in Detroit.
We drove in March and if we really needed a car at Disney that may have been different but I have some airmiles and will just get the car for the time I have the miles for.
The only thing that scares me is I have never flown southwest and I'm not to sure about this whole boarding policy but my kids are teens so I don't have the worry of them not being able to sit with me.