Trainees practice kickboxing at the Guanghan campus of Civil Aviation Flight University of China in Deyang, Southwest China's Sichuan province, Aug 20, 2016. Aviation security officers, also known as flight security officers, are responsible for guarding safety of persons on board a civilian aircraft. To become an aviation security officer is not easy. After a preliminary training for two and a half months, applicants must have at least 100-hour training on real planes. Despite the tough test, many young people want to choose this as their career.[Photo/Xinhua]