Air Marshal Melvin Hupfeld, Royal Australian air force chief, and Brig. Gen. Dato Seri Pahlawan Haji Hamzah bin Haji Sahat, Royal Brunei air force commander, watch a video at the start of the 2019 Pacific Air Chiefs Symposium on Joint Base Pearl Harbor-Hickam, Hawaii, Dec. 5, 2019. The theme of PACS 19, “A Collaborative Approach to Regional Security,” focuses on building mutual understanding of varied regional perspectives through bilateral engagements and multinational panels and meetings. (U.S. Air Force photo by Staff Sgt. Hailey Haux)