'航空' (háng kōng) literally combines '航' (háng), meaning 'to navigate' or 'to sail', and '空' (kōng), meaning 'sky' or 'air'. Together, they form the compound noun meaning 'aviation' — the science, practice, and industry of flying aircraft. It emphasizes flight through the atmosphere, distinguishing it from space travel (航天, háng tiān). The term is widely used in formal, technical, and institutional contexts, such as aviation authorities, airlines, air traffic control, and aerospace education.

In everyday usage, '航空' appears in compound words like 航空公司 (hángkōng gōngsī, 'airline'), 航空港 (hángkōng gǎng, 'airport'), and 航空安全 (hángkōng ānquán, 'aviation safety'). Unlike more colloquial terms like 飞机 (fēijī, 'airplane'), 航空 carries an official, systemic connotation — it refers to the broader ecosystem of air transport rather than individual flights or vehicles.