The period saw a shift toward human-centered automation in aviation, integrating human factors, situation awareness, and cognitive error considerations into cockpit, air traffic control, and system design. Crew Resource Management (CRM) evolved into team-based safety governance, bridging cockpit task handling, error management, and cross-system coordination across commercial aviation. Design principles and agent-based interfaces explored shared control and pilot-vehicle collaboration, while simulation and validation environments supported high-fidelity training and safety testing for both rotorcraft and fixed-wing operations; policy, externalities, and resilience perspectives framed governance and risk management in aviation safety. Historical Significance: A pivotal work on error management in aviation promoted proactive error reporting, safety culture, and organizational mindfulness, reshaping safety programs and CRM practices across the industry. Research into optimal strategies for free-flight air traffic conflict resolution demonstrated feasible, optimization-based approaches for collaborative automation and future airspace guidance. Formal requirements specification for critical aviation subsystems showed the practicality of rigorous specifications for safe aerospace software, influencing engineering standards and verification practices.