At the outbreak of war the ‘Aérostiers’ consisted of four sections with one observation balloon in Liège, one in Namur and two in Antwerp. They also had two airships. After the Battle of the Yser the ‘Aérostiers’ were sent to Calais to regroup and to receive new equipment. As from 1915 the unit became operational again, and observation balloons were used on various positions at the front.
At the end of 1917 the General Headquarters reorganised the unit in three companies with six observation balloons in total.
Between 17 May and 30 June 1918 the field journal mentioned the following:
- 141 enemy batteries observed,
- 154 times support of own artillery fire,
- 9 balloons fi red at by enemy planes and 5 of them brought down,
- 22 balloons fi red at by enemy artillery, 8 of them to no effect,
- 1 balloon damaged by bringing it down too fast,
- Cables of 2 balloons severed by enemy shrapnel,
- 20 observers who had to use their parachutes to jump.
During the 1918 offensive the ‘Aérostiers’ companies could barely keep up with the army’s advance. Furthermore, the weather conditions were unsuitable for using balloons. The balloons would be used for the last time at the Ghent-Terneuzen canal on 10 and 11 November 1918.