The Graf Zeppelin over Plaça de Catalunya, Barcelona 1929. Probably a fake of that time, zeppelins were in fashion and postcard makers added zeppelins to the sky. In this case the dirigible is too low to be safe over a built area.
SPEED, SAFETY, COMFORT - Click for more travel posters from an exhibit in Berlin. Here, a promotion by Veedol Motor Oil ("the only Motor Oil of the Graf Zeppelin"): Poster offers 30 people a free flight over the Alps, including train"free catering on board" the zep.