Airship - aircraft lighter than air balloon with an engine through which the airship can move independently from the direction of air flow.
The earliest airships were driven by a steam engine or muscular strength in 80-ies of the XIX century were used motors, c 1890 have been widely used internal combustion engines. During the XX century, airships were equipped almost exclusively on ICE - aviation, and much less diesel (on some Zeppelin and some modern airships). As the propellers used propellers. Also worth noting is extremely rare cases of turboprop engines - a dirigible GZ-22 «The Spirit of Akron» and the Soviet draft of the D-1. Most such systems, as well as reactive, remain only on paper. In theory, depending on the design of the energy of such an engine could be used to create thrust.
Climb and descent produced by tilting the airship elevators - engines then pull it up or down. Dropping ballast and release the gas in the air produce rare: for example, produce gas in the formulation of fuel. Because of this feature of the arrows on the Kaiser Zeppelin "had to get permission from the commander to fire heavy machine guns, to inadvertently ignite the released hydrogen.