AEW aircraft are used for defensive and offensive air operations. The system is used offensively to direct fighters to their target locations, and defensively to counter attacks.
Many countries have their own AEW systems, although the Boeing AWACS and Northrop Grumman E-2 Hawkeye are the popular systems worldwide. AWACS is built by the Boeing Defense and Space Group and is widely considered to be an international benchmark for AEW systems. It is based on the Boeing 707 aircraft. The Northrop Grumman E-2 Hawkeye, which entered service in 1965, is arguably the most widely used AEW system.