Since the late 1960s WDL has been using zeppelins for aerial advertising and developed a helium filled blimp specifically for that reason - a technical invention that has been setting the benchmark to this day. The WDL 1B type has been produced since 1988 and still is the biggest, commercially utilized non-rigid airship with an envelope volume of 7,200 m³ and 60 meters length.
Naturally, the technology has been steadily developed. “Night-Sign ?” is one of the WDL- innovations, which keeps airship advertising future-viable: This is a 33 m x 8 m area of lights on the airship envelope. 9,000 lights make brand logos shine at night. Also neon writings and animated films can be displayed up in the sky.