NASCARs have been taking flight at Daytona, and other tracks, since Bill France Jr was in short pants.
They were doing it before the restrictor plate was brought in, and they've done it in every generation of NASCAR since.
It will continue to happen so long as there is an opportunity for air to get under the car, when that car is not travelling in the desired direction.
It is not rocket science. It is aerodynamics and physics doing what they do.