New technologies significantly increased the reach of advertising from the late nineteenth century. Some aspects of this phenomenon, such as advances in printing methods, are well-known; others, in particular its controversial leap into the sky, have received far less attention. Though no longer seen as the home of divine portents, the sky did not become “empty space” in the modern era: it was still freighted with significance. This meant that the various attempts made by entrepreneurs from the 1880s to bring advertising to the skies were often met with hostility, even panic. In exploring these responses, this article resists depicting opponents of aerial advertising as over-sensitive aesthetes or technophobes. Rather, it explores the ways in which urbanization and commercial development imbued the sky with new meanings. The sky was imagined as man’s most valuable connection to nature in an urban society, a precious but endangered part of the nation’s heritage, and an essential counterweight to consumer society. Aerial advertising therefore represented an unjustifiable commercialization of a priceless public space. The rejection of this form of advertising did not involve denying modernity, but achieving an accommodation with it.