how do "zero g" planes work? As the title says, I'm curious about how Zero G planes work. They can't get into orbit , because there's no way they're engines could provide thrust for such speed, and they don't really leave the atmosphere. I've read that they way it's done is by simulating sort of a elevator drop effect, going up... and then dropping , and the persons inside it are floating in free fall. i understand it so far, but when the plane is dropping, and the people are in mid air.. how come the plane's back doesn't smash into them? they would have to be at the exact same velocity ( the human and plane). right?