This paper presents a survey of 68 recent conflict detection and resolution (CD&R) modeling methods, including several currently in use or under operational evaluation. The authors categorize these models based on a framework that outlines the basic functions of CD&R, including state information dimensions, dynamic state propagation methods, conflict detection thresholds, resolution methods, maneuvering dimensions, and management of multiple aircraft conflicts. The paper discusses the importance of understanding these models to improve CD&R systems, which are essential for maintaining aircraft separation in the current airspace system. The paper also critiques the current system design process, highlighting the need for a framework that can compare, contrast, and evaluate CD&R methods. The paper reviews various CD&R methods, including those based on nominal, worst-case, and probabilistic state propagation, and discusses their advantages and disadvantages. It also addresses issues such as uncertainty management, coordination between aircraft, and the balance between false alarms and loss of separation incidents. The paper concludes that there is a need for a more comprehensive approach to CD&R system design, including the use of probabilistic trajectory models and performance-based design methods. The paper also highlights the importance of considering human factors and the integration of CD&R systems with other existing systems.This paper presents a survey of 68 recent conflict detection and resolution (CD&R) modeling methods, including several currently in use or under operational evaluation. The authors categorize these models based on a framework that outlines the basic functions of CD&R, including state information dimensions, dynamic state propagation methods, conflict detection thresholds, resolution methods, maneuvering dimensions, and management of multiple aircraft conflicts. The paper discusses the importance of understanding these models to improve CD&R systems, which are essential for maintaining aircraft separation in the current airspace system. The paper also critiques the current system design process, highlighting the need for a framework that can compare, contrast, and evaluate CD&R methods. The paper reviews various CD&R methods, including those based on nominal, worst-case, and probabilistic state propagation, and discusses their advantages and disadvantages. It also addresses issues such as uncertainty management, coordination between aircraft, and the balance between false alarms and loss of separation incidents. The paper concludes that there is a need for a more comprehensive approach to CD&R system design, including the use of probabilistic trajectory models and performance-based design methods. The paper also highlights the importance of considering human factors and the integration of CD&R systems with other existing systems.