Skilled labour shortage is a well-known current issue throughout western hemisphere. It affects air navigation service providers as well in recruitment of future air traffic controllers. One promising solution is a highly-automated enhanced support system enabling a deployment of one single air traffic controller per sector instead of two for a standard layout. However, automation can be problematic if it is impossible to establish trust for humans into technology. This paper presents design and interaction methods of validated support tools and functions during a validation campaign of single controller operations, the conduct of the validation itself and mainly the results regarding design and perception of air traffic controllers for support tools. A validation was carried out with a total of seven air traffic controllers with twenty-one human-in-the-loop real-time simulation validation runs in 2023 to assess design, perception and usability of the tools proposed for single controller operations and to provide a proof of concept for the feasibility of the SCO concept and the system as a whole. A selection of seven support tools were evaluated under different traffic loads and defined frame conditions including a variety of typical controller tasks and events in air traffic control. The results presented in this paper helped to rank and select support tools and functions, to detect possible improvements in design, interaction methods, human-machine information exchange and distribution of tasks in order to empower a human single controller to perform safe, efficient and sustainable operations in a team with a digital supporting environment.