Since the first pioneering balloon flight undertaken in France in 1783, aerial ascents became an ordinary show for the citizens of the great European cities until the end of the XIX century. Scientists welcomed balloons as an extraordinary device to explore the aerial ocean and find answers to their questions. At the same time, due to the theatricality of ballooning, sky became a unique stage where science could make an exhibition of itself. Namely, ballooning was not only a scientific device, but a way to communicate science as well. Starting from studies concerning the public facet of aerial ascents and from the reports of the aeronauts themselves, this essay explores the importance of balloon flights in growing the public sphere of science. Also, the reasons that led scientists to exploit “the show of science aloft” (earning funds, public support, dissemination of scientific culture…) will be presented and discussed.