According to Wikipedia: "The Boeing 737 AEW&C is a twin-engine airborne early warning and control aircraft. It is lighter than the 707-based Boeing E-3 Sentry, and mounts a fixed, active electronically scanned array radar antenna instead of a rotating one. It was designed for the Royal Australian Air Force (RAAF) under "Project Wedgetail" and designated E-7A Wedgetail. The 737 AEW&C has also been selected by the Turkish Air Force (under "Project Peace Eagle",) and the Republic of Korea Air Force, and has been proposed to Italy and the United Arab Emirates."