The Xi'an Y-20 is a large military transport aircraft developed by Xi'an Aircraft Industrial Corporation--its official codename is Kunpeng. The aircraft made its maiden flight on January 26, 2013. In December 2013, a new Y-20 prototype took to the sky. The Y-20 is the first cargo aircraft to use 3D printing technology to speed up its development and lower its manufacturing cost. [File Photo: weibo.com]