Description: A barrage balloon is a large balloon tethered with metal cables, used to defend against low-level attack by aircraft by damaging the aircraft on collision with the cables, or at least making the attacker's approach more difficult. Some versions carried small explosive charges that would be pulled up against the aircraft to ensure its destruction. Barrage balloons were only regularly employed against low-flying aircraft, the weight of a longer cable making them impractical for higher altitudes.