The present disclosure relates to a propulsion unit for an aircraft including a nacelle which surrounds a turbojet engine. The nacelle has an inner structure surrounding a downstream compartment of the turbojet engine, and the inner structure includes two annular half-portions. The propulsion unit also includes a rail/guide unit and to move the annular half-portions between a working position and a maintenance position. In particular, the rail/guide unit radially moves away the annular half-portions relative to a longitudinal axis of the nacelle, during a translation movement of the annular half-portions. The nacelle is provided with a connecting rod which is connected to the annular half-portions and to the turbojet engine and so that the connecting rod contributes to rotate the annular half-portions about the rail.