A jet pack, rocket belt, rocket pack or flight pack is a device worn as a backpack which uses jets to propel the wearer through the air. The concept has been present in science fiction for almost a century and the first working experimental devices were demonstrated in the 1960s.

Propulsion is the generation of force by any combination of pushing or pulling to modify the translational motion of an object, which is typically a rigid body but may also concern a fluid. The term is derived from two Latin words: pro, meaning before or forward; and pellere, meaning to drive. A propulsion system consists of a source of mechanical power, and a propulsor.