A barrage balloon is a large balloon tethered with metal cables, used to defend against aircraft attack by damaging the aircraft on collision with the cables, or at least making the attacker's approach more difficult. Commonly the designs were kite balloons, having a shape and cable bridling which stabilize the balloon in windy conditions, allowing operation in higher winds than a spherical balloon. Some examples carried small explosive charges that would be pulled up against the aircraft to ensure its destruction. Barrage balloons are not practical against very high-flying aircraft, due to the weight of a very long cable.
France, Germany, Italy, and the United Kingdom used barrage balloons in the First World War. Sometimes, especially around London, several balloons were used to lift a length of "barrage net", in which a steel cable was strung between the balloons and many more cables hung from it. These nets could be raised to an altitude comparable to the operational ceiling of the bombers of the day. By 1918, the barrage defenses around London stretched for 50 miles, and captured German pilots expressed great fear of them.
Spotter Balloons were barrage balloons employed as aerial platforms for intelligence gathering and artillery spotting.
Barrage Balloons are featured in Battlefield 1.
Barrage Balloons are present in the mission Friends In High Places. They are first seen in the chapter Test Flight being used as target practice for Clyde Blackburn to test his Explosive Rockets. They are then seen in the next chapter in which Blackburn and the Royal Air Force conduct a bombing raid on an enemy fort. In order to defend their bombers, Blackburn is tasked to destroy the barrage balloons which ultimately ensures the bomber's safety.
Barrage Balloons are featured on maps set in Europe such as Argonne Forest and St. Quentin Scar. Similar to their purpose during the war, they provide a large obstacle for aircraft and will instantly destroy any vehicle that makes contact. Their use is reduced in multiplayer, however, as they are typically deployed in out-of-bound areas or on maps which do not feature aircraft. Barrage Ballons on the map St. Quentin Scar can also be destroyed by grenades and other explosive devices. When destroyed the, Barrage Ballon explodes in a fiery ball and scraps of material slowly float to the ground.
Barrage Balloons are used in the Firestorm gamemode to mark the sites of possible Resupply Points - objectives that can be captured for the reward of rare loot. Only three points are active at one time, with a balloon being raised by a cable indicating a point is becoming active.
These objectives work similarly to the flags in Conquest. When players enter the capture radius they contribute progress to the point's capture. Additional players will speed up the progress. When the point is fully captured, the balloon is ruptured releasing canisters of loot.