OAS (offensive air support)

OAS stands for offensive air support. It is an air-force role carried out in support of operations on land or at sea. NATO names offensive air support as one of the fundamental roles of air forces in both combined and independent operations, in its 1991 Strategic Concept.

The term comes from NATO and allied air-power doctrine. It is listed together with two other roles, counter-air and air interdiction, and it is a separate idea from close air support (CAS). Canadian suppliers who read defence documents will see the abbreviation alongside these related terms, so it helps to know where each one sits.

Where offensive air support sits among air-force roles

The 1991 Strategic Concept groups offensive air support with counter-air and air interdiction as the fundamental roles of air forces. Each role describes a different kind of task. Counter-air addresses opposing air power, interdiction addresses forces and supplies before they reach the fight, and offensive air support serves operations on land or at sea.

NATO describes joint air power more broadly through core roles that include counter-air, attack, air mobility and contributions to intelligence, surveillance and reconnaissance. That description is set out in NATO's official text on air power. Offensive air support belongs to this wider vocabulary of joint air power.

How OAS differs from close air support

OAS and CAS are related but not interchangeable. NATO's air-power material, including its air power video page, refers to close air support separately from offensive operations. A bid team should therefore not treat the two abbreviations as synonyms when reading a requirement.

Offensive operations in NATO air and missile defence

NATO also uses the language of offensive operations in its air and missile defence doctrine. The NATO Integrated Air and Missile Defence Policy, published in February 2025, states that offensive operations can reduce, neutralise or destroy air and missile threats before an adversary can employ them.

That passage describes a defence concept. It is not a definition of OAS, and readers should keep the two apart.

Where to confirm NATO terminology

NATO's official terminology resource is NATOTerm. It is the database of non-classified military terminology relevant to NATO. It is maintained by the NATO Terminology Office, which forms part of the NATO Standardization Office. When a solicitation relies on NATO vocabulary, NATOTerm is the reference to check first.

What OAS means for a supplier bidding on Canadian public contracts

OAS is a doctrinal term, so it will most often appear in the operational context of a requirement rather than as a product specification. Bid teams should read the statement of work and any referenced doctrine to see how the buyer uses the term, and confirm whether the requirement concerns OAS, CAS or another air-force role. Keep your response language consistent with the solicitation's own wording. Where a document points to NATO terminology, check it against NATOTerm and the NATO texts cited above. Publicus tracks Canadian defence solicitations so that bid teams can review the exact wording of each requirement before they respond.