Cao Shuang (C), an airborne security guard of China South Air, buys food at a market in Sanya, southernmost China's island province of Hainan, March 4, 2013. (Xinhua/Xu Qintao) 

Cao Shuang, an airborne security guard of China South Air, performs security check on an airliner at the Phoenix International Airport in Sanya, southernmost China's island province of Hainan, March 4, 2013. (Xinhua/Xu Qintao) 

Cao Shuang, an airborne security guard of China South Air, prepares lunch at her home in Sanya, southernmost China's island province of Hainan, March 4, 2013. (Xinhua/Xu Qintao) 

Cao Shuang (R), an airborne security guard of China South Air, trains at the airline's base in Sanya, southernmost China's island province of Hainan, March 4, 2013. (Xinhua/Xu Qintao) 

Cao Shuang (C), an airborne security guard of China South Air, boards a bus with aircrew members for the Phoenix International Airport in Sanya, southernmost China's island province of Hainan, March 4, 2013. (Xinhua/Xu Qintao) 

Cao Shuang (1st R), an airborne security guard of China South Air, helps an elderly passenger board an airliner at the Phoenix International Airport in Sanya, southernmost China's island province of Hainan, March 4, 2013. (Xinhua/Xu Qintao) 

Cao Shuang, an airborne security guard of China South Air, inspects a passenger's bag at the Phoenix International Airport in Sanya, southernmost China's island province of Hainan, March 4, 2013. (Xinhua/Xu Qintao) 

Cao Shuang, an airborne security guard of China South Air, dresses for work in Sanya, southernmost China's island province of Hainan, March 4, 2013. (Xinhua/Xu Qintao) 

Cao Shuang (1st L), an airborne security guard of China South Air, trains with male colleagues at the airline's base in Sanya, southernmost China's island province of Hainan, March 4, 2013. (Xinhua/Xu Qintao) 

Cao Shuang, an airborne security guard of China South Air, trains at the airline's base in Sanya, southernmost China's island province of Hainan, March 4, 2013. (Xinhua/Xu Qintao)