Group 1 - The core incident involves Air China's flight CA1339, which took off from Beijing to Guangzhou on November 7, returned to Beijing shortly after takeoff, and then took off again later that day [2][5] - The flight departed from Beijing Capital Airport at 12:29 PM, returned at 1:19 PM, and took off again at 3:49 PM, arriving in Guangzhou at 6:45 PM [5] - The flight experienced severe turbulence around 12:47 PM before the return [5] Group 2 - Air China confirmed the return of flight CA1339 was due to reasons attributed to the airline itself [2][5]