Group 1 - The export of American aircraft engines and components to China has resumed after a previous suspension, confirming the restoration of supply from companies like GE Aviation [2] - The C919 aircraft's delivery was not significantly impacted by the suspension of engine exports in June due to existing inventory held by COMAC [1][4] - The LEAP-1C engine, produced by a joint venture between GE Aviation and Safran, is the only overseas powerplant for the C919, highlighting the reliance on foreign technology in China's aviation sector [4] Group 2 - Boeing has resumed the delivery of aircraft to Chinese airlines, including the Boeing 737 MAX and 787, which had been temporarily halted due to trade tensions [3][6] - The exemption of tariffs on aircraft and certain engine components allows Chinese airlines to import planes at previous tax rates, which are 5% for narrow-body and 1% for wide-body aircraft [7] - In 2018, Boeing delivered a quarter of its new aircraft to China, indicating the significance of the Chinese market for Boeing's business [7] Group 3 - The Changjiang-1000A engine, China's first fully independent turbofan engine, is currently undergoing flight testing and awaits certification for commercial use [5] - The Chinese government has emphasized the need for self-sufficiency in aviation engine development, as highlighted in the "13th Five-Year" national strategic emerging industries development plan [4]