Close air support

In military tactics, close air support (CAS) is defined as air action by fixed or rotary winged aircraft against hostile targets that are close to friendly forces, and which requires detailed integration of each air mission with fire and movement of these forces.

The determining factor for CAS is detailed integration, not proximity. CAS may need to be conducted far from friendly forces, if the mission requires detailed integration with the fire and movement of these forces. A closely related subset of air interdiction, battlefield air interdiction denotes interdiction against units with near-term effects on friendly units, but which does not require integration with friendly troop movements. The term "battlefield air interdiction" is not currently used in US joint doctrine. Close air support requires excellent coordination with ground forces. In advanced modern militaries, this coordination is typically handled by specialists such as Joint Fires Observers, Joint Terminal Attack Controllers (JTAC)s, and Forward Air Controllers (FAC).