In effect the cancellation of gravity by centrifugal force is already used in so called "Vomit Comets" which are aircraft flown in parabolic arcs to briefly simulate zero g conditions for training astronauts, etc.

The apex of the parabola is approximately circular and motion along this path can be thought of as producing an upward centrifugal force which exactly counteracts the downward force of gravity. This is just another way of saying that the aircraft and its passengers are in free fall.