In this work we propose several solutions for the improved security of the selected wireless communication systems used in ATM. We review technological characteristics and properties of the two wireless communication systems: CPDLC and TCS. Basing on their specifics we construct threat models and propose a set of corresponding countermeasures. We emphasize the importance of creating cybersecurity threat model, which identify all possible cyber threats to ATM information systems, enabling the ATC authorities to be proactive and comprehensive in their approach to cyber security. In addition, we consider an example genuine security solution which implies global changes in the whole Air Traffic Communication System. The studies confirmed there is an urgent need to protect the ATM-related technologies from the wide spectrum of cyberattacks, and the solutions need to be implemented in a timely manner. Further investigations should uncover the feasibility and applicability of the proposed measures in the narrowed scope for implementation.