- At the highest point of the parabola, passengers briefly experience 3 minutes of free fall weightlessness before the plane levels off again into traditional flight (see diagram).
>The reason people inside feel weightless at the top of the trajectory is because when the jet reaches the top of the flight arc and nosedives downward, everyone, along with the jet, are in free fall. During these roughly zero-G sections of the flight, objects and people inside appear to drift around inside the cabin just like they do inside the International Space Station (ISS).
