In Vol. 31, No. 3, our journal prepared three review articles, an original paper, and two case reports. First, as COVID-19 continues for a long time, aviation workers, including pilots, are also experiencing mental problems such as depression. Therefore, we have compiled the basic principles for improving the mental health of pilots. Next, it is difficult to properly perform cardio-pulmonary resuscitation (CPR) when a cardiac arrest situation occurs in an aircraft. Moreover, in the context of the COVID-19 pandemic, CPR is more difficult because medical staff and other passengers may also be exposed to infections. Therefore, we have summarized the principles of CPR on board and ways to perform CPR while keeping the safety of medical staff and other passengers in the COVID-19 situation. The sudden change of gravity caused by space travel has various effects on the human body, and among them, the effect on the immune system is profound. Therefore, we reviewed the research methods to study the effect of gravity on the immune system and the results. In addition, we analyzed the demographic characteristics and health status of immigrant visa applicants who intended to immigrate to the United States over the past five years. Next, through two case reports, we reported cases of determining physical fitness for aviation service in patients who recovered after receiving appropriate treatment for chronic myeloid leukemia or renal cell carcinoma.