Actually in Nascar, they use side windows (on the right side only) on any track over a mile long (or maybe it is 1 1/2 mile tracks).

The problem with drag race cars (at least the ones with wings) is that once the car turns the air gets under the wings and lifts the car off the ground. That is why Nascar went back to the spoilers after trying the wings for a couple of years.

Roof flaps might actually work in drag racing. I don't really know if they will or not but no one will no unless they test it.