Abstract: An aircraft propulsion system is disclosed having an exhaust nozzle structure having an exhaust deflection structure extending within an exhaust duct to direction exhaust flow along selected flow paths. In its preferred embodiment, the exhaust deflection structure is a variable geometry deflection structure having a distal end portion which is movable, relative to adjacent aircraft structure, within an exhaust duct whereby the exhaust deflection structure is positionable as an extension of an upper, aft wall portion of the exhaust duct. In the preferred embodiment, the exhaust nozzle structure includes a guide structure or nozzle segment, connected to the exhaust deflection structure, which is translatably mounted to adjacent aircraft structure for permitting fore and aft movement of the nozzle segment along the aircraft structure.