The key R&D activity covers a concept that consists of assigning aircraft to ATCOs without references to geographical sectors, and have the aircraft controlled by that same ATCO across two or more geographical sectors. This requires flight-centric specific allocation, visualization (traffic filtering), coordination tools (e.g. in the event of a conflict, establish which controller is responsible for its resolution) and, for high traffic densities advanced CD&R tools (that are not flight-centric specific). The R&D activity also covers the concept of collaborative control with planned boundaries in which sectors are retained as they are today, with aircraft being assigned to a sector according to its geographic location. The boundaries between sectors have planned coordination conditions like in current operations, but with some additional flexibility by allowing controllers to issue clearances without prior coordination to aircraft in a different sector.