There was a time when husbanding scarce resources was considered the patriotic American thing to do. See more of this WW2 bike safety pamphlet at FixedGear’s Flickr stream.
Before America entered the war, bicycles were largely used as a means of recreation and pleasure, and for riding to and from school by young people. Now they are helping to provide essential wartime transportation as well. More and more people are riding bicycles to and from work, for shopping, for errands, and for other purposes.”