Xi'an Xiguan Airport — Xi'an (Baqiao), China

SIA refers to Xi'an Xiguan Airport, a historical airfield associated with the city of Xi'an in Shaanxi Province, China. Xi'an, famed as home to the Terracotta Army and an ancient imperial capital, has long been served primarily by the larger Xi'an Xianyang International Airport, with Xiguan functioning as an older or secondary facility in the city's aviation history. Details on Xiguan's current operational status are limited, as much of Xi'an's modern civil aviation traffic has shifted decisively to Xianyang's expanded terminals. The SIA code nonetheless remains tied to Xi'an's broader identity as a major cultural and historical destination in northwestern China, drawing millions of tourists annually to its ancient sites.