On December 7th, 2022, the Chinese State Council held a press conference and released a notification on further optimizing the COVID-19 control policies. This signifies that all COVID-19 pandemic control measures in China have been eased. The transformation in the Chinese government's attitude towards COVID-19 prevention and control has had a significant influence on China's market and most industries. This change has also had an undeniable impact on certain industries, especially the air transportation industry in developed countries around the world, including Japan, which is China's most important neighboring country. This paper focuses on the Japanese air transportation industry, specifically analyzing the Nikkei-500 and TOPIX indices. It collects weekly closing data from April 26th, 2020, to April 23rd, 2023, and utilizes the ARIMA model to analyze the data. The aim is to explore how the Japanese air transportation industry has been affected by the relaxation of COVID-19 pandemic control policies in China. Furthermore, this paper discusses the insights gained from the research findings and provides advice for policymakers and investors.