I guess it depends on exactly what point we consider the state of flying to have ended during a crash. The second the plane first makes contact with the ground, or after all of the fragments stop moving?
I think it comes out in favor of flying either way, but for sure the second makes it pretty lopsided. It limits the possibilities of OnPlane && !Flying to waiting for takeoff, and since you spend more time in the air than grounded even death by natural causes in flight would overtake death while grounded.
It's usually the not-flying that kills you