[snip]
My father had a long argument at his sailing club about being able to 'sail' directly into the eye of the wind. He built a small prototype of a wind driven 'propeller' directly shaft coupled to a water propeller that proved his point.
The significant factor, as with all methods of extracting power from wind, is that there is a relative wind blowing over the collector. This of course wouldn't apply in the case of an airship unless tethered or having another source of power.
Pete