Collaborative air traffic flow management (ATFM) has evolved beyond issues around excess traffic to now contribute in all instances to a safer, more orderly, expeditious and environmentally sustainable flow of air traffic, and to support cross-border collaboration. This evolution is about ensuring that air traffic control capacity is optimized and utilized to the maximum extent possible. This session will provide an overview of proposals for amendment to Annex 11 and PANS-ATM, which will become applicable in the coming years. The subject of the amendment includes: the measuring of air traffic control capacity for controlled airspace and controlled aerodromes at the national level; multi-States arrangements and centralized organization; the ATFM framework at the national and regional levels highlighting the required regulations, organizational structure and functions, operating procedures, etc. The session will also share the current ATFM implementation experiences and challenges.