Bozeman Yellowstone International Airport is eight miles northwest of Bozeman, in Gallatin County, Montana. Owned by the Gallatin Airport Authority, the airport is in Belgrade and has recently become the busiest airport in Montana for passenger service.The National Plan of Integrated Airport Systems for 2011–2015 categorized it as a primary commercial service facility . Federal Aviation Administration records say the airport had 442,788 passenger boardings in calendar year 2013, 434,038 in 2012 and 397,870 in 2011.HistoryIn 2011 a terminal expansion designed by Prugh & Lenon Architects opened, adding three gates and more retail concessions. The firm designed expansions and renovations made in 1995 and 1997.Gallatin Field was renamed Bozeman Yellowstone International Airport in late 2011 to associate it with Yellowstone National Park. International flights have been allowed since 2012, after a U.S. Customs and Border Protection facility opened on July 1. The project was funded in cooperation with Signature Flight Support and the Yellowstone Club. In 2013, BZN surpassed Billings as the busiest airport in Montana for passenger service with 879,221 passengers from June 2012 to May 2013.