Balancing controller workload is part of the air traffic management (ATM). It is the current practice to organize airspace and balance its demand and capacity by partitioning airspace into sectors. This approach is naturally limited by the minimum size of sectors and the amount of possible controller coordination. The approach considered in this thesis is examined in the joint project called “Airspace Management 2020” (LRM2020) by DFS (Deutsche Flugsicherung GmbH) and DLR (Deutsches Zentrum fur Luft- und Raumfahrt e.V.). The aim is to provide a sectorless airspace. For this concept, the possibilities for the assignment of aircraft to air traffic controllers are examined. Different assignment strategies have been developed and selections of these are tested with various traffic scenarios on their capacitive properties.