People carry a poster showing the "Flying Tigers" pilots during a ceremony at the Air Force Memorial in the outskirt of Washington D.C. on May 28, 2012. The Flying Tigers, a U.S. volunteer group which fought alongside the Chinese against Japanese aggressors in World War II, were honored in a ceremony Monday by the Air Force on the country's Memorial Day, a day of remembrance for the men and women who died while serving in the armed forces. [Xinhua]