The intense urbanization of cities has left few options when it comes to insert large mobility infrastructure they need to move their inhabitants. A surface rail network, a dedicated roadway bus line or any other mobility infrastructure such as a tramway at the urban surface represent challenging interfaces to set up, particularly because of level crossings and physical barriers that they induce in the urban space. To avoid this occupation of the surface and the resulting urban scars, a lot has already been invested in the underground. Whilst, the airspace is still very little exploited by urban transport systems. In order to deepen knowledge in this area, the research theme focused on the urban ropeways, a cable air transport system, which several innovative examples can be found in Latin America. Relevant for whom? The research conducted is divided into two stages. As a first step, a sociological analysis made it possible to determine how urban ropeways are relevant for users and represent an interesting alternative to other means of public transportation. This analysis is based on a survey among users of ten public transportation lines in Switzerland and Brazil. Relevance where? In a latter phase, the analysis concerns the project of urban ropeways in the urbanized areas. This transportation system can be considered as a complex project because of its constructive characteristics, at the territorial big scale. A sequence of large mobility interfaces projected along the ropeway path transforms connectivity, density, and public space. These different architectural objects of mixed use are connected in minutes by the cable and their strong presence in the urban landscape raises questions of relevance. Spread in the Rio de Janeiro, Lake Geneva and New York metropolis, ten cable routes are studied, taking into account the temporality of project progress and the degree of urbanization of the target territory. This evaluation of the project practice aims to determine the extent to which urban ropeways is likely to be developed in European territory, Swiss in this instance. At the end of these analysis, the thesis makes it possible to conclude that urban ropeways have their relevance in European cities, but under fairly specific conditions.