content: There's got to be a lot of editing going on there. According to wiki: https://en.wikipedia.org/wiki/Reduced_gravity_aircraft   This aircraft is used to train astronauts in zero-g maneuvers, giving them about 25 seconds of weightlessness out of 65 seconds of flight in each parabola. During such training the airplane typically flies about 40–60 parabolic maneuvers.  You can see in the video where they gain weight at certain places. But I'd still think this had some editing going on. If that was all one take of multiple parabolas, that's a pretty amazing video.