The continuously increasing air traffic density has become a major challenge in air traffic control (ATC) due to the current ATC systems are approaching maximum capacity. To deal with the problem, an automated conflict resolution aid (CRA) and a trajectory prediction aid (TPA) have been proposed to serve as additional safety layers in the ATC systems. However, whether the proposed automation aids are worth to be applied in the current ATC workplace and could better support air traffic controllers (ATCOs) remain unknown. This study aims to investigate the effects of the proposed automations on ATCOs' workload and situation awareness (SA). To do so, twenty-four participants were evenly divided into two groups corresponding to the presence and absence of the TPA. In each condition, participants were instructed to perform simulated ATC tasks with the double of current air traffic load under the presence and absence of the CRA. The results showed that the CRA benefits ATCOs' workload and SA. The application of the CRA alone could benefit ATCOs while the presence of the TPA alone did not offer valuable benefits for ATCOs. Importantly, the CRA could lower the workload substantially when it was integrated with the TPA. The automation design aspect and its application in enhancing safety of future ATC are also highlighted.