CATS hosted the 21st Meeting of Asia-Pacific Cross-Border Multi-Nodal ATFM Collaboration (AMNAC/21) from 12 – 15 March 2024 at Sokha Phnom Penh Hotel, Cambodia. Approximately 66 people from 11 countries attended the meeting. The AMNAC Project is a project that plays an important role in arranging standard practices for the Air Traffic Flow Management (ATFM) for the Asia-Pacific region, which has begun concept development since 2015. This AMNAC/21 meeting aims to review ATFM practices, processes and agreements between various agencies within the region, as well as review performance and discuss future project development trends to enhance the quality of ATFM operations that will lead to maximum efficient and safe air traffic management in the Asia-Pacific region.