Additive manufacturing (AM) is an advanced manufacturing technology with many potential sustainability benefits, especially in the aerospace industry. This includes the possibilities to produce complex lightweighted (hollow) components, reducing fuel consumption for aircrafts. Outside of the use phase, there are still challenges to overcome in terms of understanding environmental and sustainability benefits. The purpose of this study was to investigate the life cycle properties and compile findings regarding AM of metal components, in order to assess its impact on the environment and sustainability. This includes an overview of AM, a quantitative life-cycle investigation of superalloy IN718 and a qualitative sustainability assessment of AM using Ashby's five-step method and a discussion in terms of Circular Economy. Results from a life-cycle inventory (LCI) show that both AM-methods, electron beam melting and selective laser melting in this case, required significant specific energy in manufacturing (including powder production), comparable to the embodied energy of the raw material itself. The energy-use is highly dependent on the geometry of the build though and AM offers many advantages in all three sustainability dimensions. This is, amongst other things, due to potential in material savings and closing material loops, freedom in design, on-demand production as well as possibilities for repair and refurbishment. Results also showed that AM have opportunities for better material efficiency than conventional methods, in a circular economy model. One conclusion was that AM-technologies, due to slow build time and relatively high energy consumption (depending on geometry), is not yet feasible for mass production but rather suits small batches of customized or complex components.