If so why less likely to fly? By which design changes?
Or just less likely because most racetracks reduced straight lengths and thus top speeds?
Why mostly 1990s+ prototypes began to fly?
http://www.popsci.com/cars/article/2008 ... cecars-fly
http://www.youtube.com/watch?v=nkcGPf-fLV0
Maybe as they banned/limited venturi tunnels thus mandating flat bottoms with less downforce.
Would Nascar style roof flaps prevent them from going flying?
http://en.wikipedia.org/wiki/Roof_flap
Are open top prototypes less likely to take off?