A lightweight inflation device for outputting a low-pressure airflow to inflate an air bladder includes a body defining an airflow chamber and a plurality of air manipulation elements disposed within the airflow chamber. At least one of the air manipulation elements is a rotor including a plurality of blades, and the inflation device includes a driving mechanism operable to rotate the blades about an axis. The inflation device further includes a nozzle operably coupled with the body and defining an air outlet to connect with a valve on the air bladder. The nozzle is shiftable into an operating position in which the air outlet extends beyond an outlet-side axial margin of the body. The nozzle is also shiftable into a storage position in which the air outlet is disposed within the airflow chamber of the body. A method of inflating an air bladder with a portable axial compressor assembly is also disclosed.