In last years the additive manufacturing technologies (AM) have been subject to a continuous and rapid development and there are a lot of applications in every industrial sector. Even if the aerospace sector should be one of the main users, it is still very focused on traditional manufacturing technologies due to the severe certification and quality constraints. Generally, the latter give rise to high development costs and, if not compensated with extremely efficient designs, it leads to the non-adoption of additive technologies, missing a great opportunity. The present work aims to present some applications concerning the AM in the aerospace sector, developed in the framework of several CIRA research programs and focused on the whole development path that include design, manufacturing and testing. A first application consists in the design, manufacturing and testing of venting flanges for aeronautical bladder tanks. Considering the original design, based on traditional manufacturing technologies, it has been improved in order to guarantee the requirements fulfilment and to exploit the additive potential. The second application concerns the redesign of the connection flanges for a space launcher primary structures made by CFRP Anisogrid. The activities were focused on the use of AM for improving the global mechanical performance and, at the same time, for saving manufacturing and assembly costs. The last application concerns the development of crash absorbers for aeronautical applications, based on lattice structure concepts. The study is still on going and it is focused on the development of specific interfacing structures used to install hydrogen tanks in commercial aircraft fuselages and able to guarantee the same safety level of conventional fuel storage systems from a crashworthiness point of view. The work therefore offers a quick overview of some success stories and of what could be a future use of additive technologies, highlighting the problems connected to the particularity of the process both from the point of view of production and design.