The digitalisation of work is associated with a range of technologies, including digital platforms and so-called artificial intelligence (AI), as well as ideas about how they will improve productivity and competitiveness. This article analyses how unions anticipate the consequences of digital technologies and how they mobilise to address their impact on employment, skills, and quality of work. Drawing on qualitative research conducted in aerospace manufacturing in Belgium (Wallonia), Denmark and Canada (Quebec), our findings suggest that unions are mobilising contrasting frames and repertoires of action, drawing on traditional institutions, and experimenting with new ones to shape the future of work in the aerospace industry.