Thus , flight proceeds in a leisurely vertical zig - zag pattern .
In this way , an airship can gain aerodynamic forward thrust like any other glider , by periodically alternating its buoyancy between positive and negative while adjusting its attitude accordingly .
Flight proceeds in a leisurely vertical zig - zag pattern .
In this way , an airship can gain aerodynamic forward thrust like any other glider , by periodically alternating its buoyancy between positive and negative while adjusting its attitude accordingly .