Military engines typically employ articulated engine nozzle systems, which are configured around the engine outlet and appear as a series of individual movable metal elements. As a result, the entire assembly is sometimes referred to as the "turkey feathers." The assembly increases or decreases the outlet diameter at various throttle positions in order to alter engine thrust.
Static aircraft engine nozzles are just that--static. You will typically see these nozzles at the back of commercial airliners with fan-jet engines, and they are configured to produce a steady and mean pressure level at the back of the engine. In this case, increases and decreases in power rely entirely on the engine's RPM, and that process is created by airflow through a stator disk at the front of the engine. Nozzles for these kind of systems are typically bell shaped and integrated with the engine as a single piece to aid speed of maintenance.
Movable and articulated nozzles are a fairly new advancement, although the engineering community has known the concept for some time. These systems, typically seen on military aircraft, emerged as production variants during the last ten years. Some refer to these systems as paddle nozzles, since opening or closing the engine outlet is based on a flat clam-shell configuration, in addition to operating a full range of movement up, down and left or right. In this case, when the pilot commands a left or right turn, the nozzle itself turns to the left or right to reduce the aircraft's radius of turn. At the same time, if the pilot pulls or pushes on the stick, the nozzle points up or down and helps alter the airplane's pitch more quickly. Today, this series of movements is sometimes referred to as "pointing" the airplane.