The present work is an attempt to improve the characterization and quantification of the performance of dielectric barrier discharge (DBD) plasma actuators for aerodynamic flow-control applications. Existing measurement and evaluation strategies, together with additional new approaches have been applied and are discussed extensively. Novel scaling numbers are introduced that yield universal and partly non-dimensional key quantities for an improved evaluation of the electrical discharge characteristics and of the environmental influences about the behavior of plasma actuators. The existing strategies to quantify the momentum transfer from the plasma to the surrounding air are reviewed and have been applied to achieve a comprehensive and comparative analysis of the respective differences based on experimentally obtained data. Direct and implicit as well as differential and integral force estimation approaches are discussed. To counteract influences of the environment on the discharge and thus assuring constant plasma-actuator performance, a closed-loop control circuit of the electrical setup is introduced and successfully demonstrated in a proof-of-concept experiment.