No commercial Flights King County International Airport—also known as Boeing Field—is one of the busiest primary non-hub airports in the nation. The airport serves small commercial passenger airlines, cargo carriers, private aircraft owners, helicopters, corporate jets, and military and other aircraft. It is also home to the Boeing Company’s 737 aircraft flight-test program, along with other Boeing operations. The Museum of Flight is located there, with its wide variety of aircraft and exhibits showcasing aviation history. It is frequently host to celebrities and dignitaries, including the President of the United States, who prefer Boeing Field because of its proximity to downtown Seattle and other commercial areas.