This article addresses the inability of the Second Republic to take the reins of action against aircraft throughout the loyal territory, offering in turn a brief overview of the resulting defensive mosaic and its subsequent attempt to overcome it. To this end, a brief analysis of the republican context in terms of anti-aircraft defense from 1935 to 1937 is presented, emphasizing the legislative order of the first year of the war. After that, some of the main local and regional initiatives that overlapped with the government's provisions are presented, thus further tensing the Republic's springs and generating a sort of parallel order.