NASCAR has really struggled with the aero on these cars. I noticed when cars pulled up behind each other as the car behind approached it would make the lead car loose and then the trailing car would close the last couple of feet like slamming a door.
IMO, they need to get air going under the cars again and leave more to the drivers. Ryan Newman drove like his nickname suggests - Rocketman - and was within feet of winning and damn near got killed.
When they are flying wings, they are not race cars. The only answer is slowing them down to say 100mph, and that will never happen.