What system do dirigibles have that distinguishes them from traditional hot air balloons?

Dirigibles, also known as airships, are characterized by their ability to be steered and controlled in flight, which distinguishes them significantly from traditional hot air balloons. While both use buoyant gases to achieve lift, hot air balloons are reliant on thermal rising air and lack any directional control; they move solely with the wind. In contrast, dirigibles are equipped with a steering mechanism that allows pilots to change direction and altitude, offering greater navigational capabilities. This system typically includes rudders and elevators, allowing for precision in movement.

In addition, while dirigibles may feature lighter-than-air gases and combustion engines, these elements alone do not define their unique capacity for controlled flight. A lighter-than-air gas, like helium or hydrogen, is common to both dirigibles and balloons, and while some dirigibles may have a rigid framework, not all do; many modern airships have a non-rigid structure. Therefore, the defining characteristic that sets dirigibles apart in terms of functionality is their advanced steering mechanism.