This san serif font printed on an air circus advertisement in the 1920’s caught my eye.  The simplicity of the letters follow the theme of the poster, which is to catch the attention and make it easy to read.  The bold body of each letter makes it the focal point of the poster, which then leads your eye down the page.  This poster is meant for advertising, so the fact there are so serifs or detail on the heading letters make it easy for a passersby to read easily with no effort, then possibly stop to read the rest of the poster.  Because there is so much information on the poster, a more decorative font would have made it look cluttered and hard to read, but since it is simplistic and almost gothic, it is more pleasing to the eye.  The letters are spaced just right so there is no over or under compression to strain the reader.  There is no material behind the font, just the simple modularity to advertise the airshow.