Chicago Hub is a term used to refer to the two major airports in the city of Chicago, Illinois. ORLY is the acronym for the O'Hare International Airport, which is the primary airport serving the city and one of the busiest airports in the world. OHARE is the acronym for the Midway International Airport, which is the secondary airport serving the city and is located on the southwest side of the city. Together, these two airports form the Chicago Hub, providing air travel services to millions of passengers each year.