Sion Airport PC-6, Pilatus PC-7, Pilatus PC-9 and Pilatus PC-21 as well as helicopters it uses Sion intensively with the fighter jets F/A-18 and F-5 Tiger. It is the home base of the militia pilot unit Fliegerstaffel 19 Swans with F-5E. Sion Airport is, at both ends of the runway, equipped with retractable arresting gear devices (used by the F/A-18 and in case of a problem by the F-5). Because of the redimension of the Swiss Air Force it is planned that the Air Force will leave Sion after 2017 and Sion will be used by civil aviation only, acting only as
Sion Mills of Finn") or "Sidheán" (also spelt "Síodhán" and "Sián", meaning "fairy mound"). The second part of the name is the English "mill". Sion Mills was laid out as a model linen village by the Herdman brothers, James, John and George. In 1835 they converted an old flour mill on the River Mourne into a flax spinning mill, and erected a bigger mill behind it in the 1850s. However, nearly everything in Sion Mills today was designed later, in the 1880s and 1890s, by James Herdman's son-in-law, the English architect William Frederick Unsworth. Sion House, a half timbered Elizabethan style mansion