Our times are characterised by involuntary immobility as much as by large migration flows. The sheer number of people wishing to migrate but not being able to do so indicates that migration must be analysed in the light of restrictive immigration policies. This article suggests that insights can be gained by addressing the aspiration and ability to migrate separately. On the basis of a case study of emigration from Cape Verde, the article first examines how aspirations are formed in the interplay between people's individual characteristics and their common emigration environment. It then proceeds to investigate how potential migrants' ability to migrate is determined in their encounter with the immigration interface. This involves a series of barriers and constraints which each potential migrant is differently equipped to overcome. The aspiration/ability model is proposed as a framework for analyses of migration and non-migration at a time when mobility itself has become an important stratifying factor.