Editing Aircraft (section)

==== Aerostats ====
{{Main|Aerostat}}

[[File:OAM_Aerostat_TARS_Deming_New_Mexico_(16715553462).jpg|thumb|A modern aerostat used by the [[U.S. Department of Homeland Security]], the [[Tethered Aerostat Radar System]] (TARS)]]

An ''aerostat'' or ''lighter-than-air aircraft'' relies on [[buoyancy]] to maintain [[flight]]. Aerostats include unpowered [[balloon (aircraft)|balloon]]s (free-flying or [[moored balloon|tethered]]) and [[aircraft engine|powered]] [[airship]]s. The [[relative density]] of an aerostat as a whole is lower than that of the surrounding [[atmospheric]] [[air]] (hence the name "lighter-than-air"). Its main component is one or more gas capsules made of lightweight [[skin (aeronautics)|skin]]s, containing a [[lifting gas]] (hot air, or any gas with lower density than air, typically [[hydrogen]] or [[helium]]) that [[displacement (fluid)|displace]]s a large volume of air to generate enough buoyancy to overcome its own [[weight]]. [[Payload]] (passengers and cargo) can then be carried on attached components such as a [[basket]], a [[gondola (airship)|gondola]], a [[cabin (aircraft)|cabin]] or various [[hardpoint]]s.<ref>{{Cite book|url=https://books.google.com/books?id=pz2ORay2HWoC|title=The Chambers Dictionary|last=Chambers|first=Allied|date=1998|publisher=Allied Publishers|isbn=9788186062258|page=541|language=en|quote=the gas-bag of a balloon or airship}}</ref><ref>{{cite book |title=The Oxford Illustrated Dictionary |page=281 |publisher=Oxford University Press |year=1976 |orig-year=1975 |location=Great Britain |quote=fabric enclosing gas-bags of airship}}</ref> With airships, which need to be able to fly against wind, the lifting gas capsules are often protected by a more rigid outer envelope or an [[airframe]], with other gasbags such as [[ballonet]]s to help modulate buoyancy.

Aerostats are so named because they use [[aerostatic]] buoyant force that does not require any forward movement through the surrounding air mass, resulting in the inherent ability to [[levitation (physics)|levitate]] and perform [[vertical takeoff and landing]]. This contrasts with the heavier-than-air [[aircraft#Heavier-than-air|aerodyne]]s that primarily use [[aerodynamic]] [[lift (force)|lift]], which must have consistent airflow over an [[aerofoil]] ([[wing]]) surface to stay airborne. The term has also been used in a narrower sense, to refer to the statically [[tethered balloon]] in contrast to the free-flying airship.<ref>{{cite book |title=A Dictionary of Aviation |first=David W. |last=Wragg |isbn=9780850451634 |edition=first |publisher=Osprey |year=1973 |page=8}}</ref> This article uses the term in its broader sense.