The duration of air time on a particular hill is dependent on the velocity of the train, gravity, and the radius of the track's transition from ascent to descent.
Floater air time provides passengers with the sensation of gently floating upwards, which can be described as near perfect weightlessness.
Roller coasters built by the manufacturing company Rocky Mountain Construction are famous for providing ejector air time.
For example, in the case of The Twilight Zone Tower of Terror at Disney's Hollywood Studios, Tokyo DisneySea, and Disneyland Paris, the elevator drops riders faster than gravity normally would, causing them to rise off of their seats by several inches whilst being held down by only a seat belt, creating the sensation of zero-G.
Most drop towers, however, have shoulder bars, preventing riders from rising significantly from their seats, even where negative Gs are present.