Offensive counter-air (OCA) is a military term for the suppression of an enemy's military air power, primarily through ground attacks targeting enemy air bases: disabling or destroying parked aircraft, runways, fuel facilities, hangars, air traffic control facilities and other aviation infrastructure. Ground munitions like bombs are typically less expensive than more sophisticated air-to-air munitions, and a single ground munition can destroy or disable multiple aircraft in a very short time whereas aircraft already flying must typically be shot down one at a time. Enemy aircraft already flying also represent an imminent threat as they can usually fire back, and therefore destroying them before they can take off minimizes the risk to friendly aircraft.
Air-to-air operations conducted by fighter aircraft with the objective of clearing an airspace of enemy fighters known as combat air patrols can also be offensive counter-air missions, but they are seen as a comparatively slow and expensive way of achieving the final objective - air superiority.[1] The opposite term is defensive counter air, primarily referring to the protection of territory, men and/or materiel against incursion by enemy aircraft, usually with a combination of ground-based surface-to-air missiles and anti-aircraft artillery but also through defensive combat air patrols.