PRESIDING JUSTICE O'MALLEY delivered the opinion of the court:

Defendants the Department of Revenue (Department), Brian A. Hamer (in his official capacity as director of the Department), Du Page County Board of Review, West Chicago Elementary School District No. 33, City of West Chicago, West Chicago High School District No. 94, West Chicago Park District, West Chicago Fire Protection District, and West Chicago Library District appeal the decision of the circuit court of Du Page Countyreversing the decision of the Department and ruling that certain property belonging to plaintiff, the Du Page County Airport Authority, fulfills an airport authority purpose and is thus tax exempt. For the reasons that follow, we reverse the decision of the circuit court of Du Page County and affirm the ruling of the Department.

I. FACTS

The parties stipulated to the relevant facts, which we briefly recite here. Plaintiff is an airport authority created pursuant to the Airport Authorities Act (Act) (70 ILCS 5/1 et seq. (West 2000)). By virtue of the authority granted it under the Act, plaintiff owns, operates, and maintains the Du Page Airport (Airport), a general aviation airport, and owns property leased to various tenants, including private, for-profit, commercial entities, all on approximately 2,800 acres of land in West Chicago, Illinois. As a general aviation airport, the Airport accommodates a mix of air traffic ranging from single-engine, propeller-driven aircraft and helicopters to large, high-performance jets. There are no commercial carriers using any of the Airport's facilities. In real estate tax year 2000, plaintiff's maximum real estate tax rate by statute was 0.0306, and the actual tax ratefor plaintiff's real estate tax levy was 0.0291.

This appeal involves 65 tax parcels, which plaintiff claims are exempt under section 15--160 of the Property Tax Code (Code) (35 ILCS 200/15--160 (West 2000)) as fulfilling an "Airport Authority purpose." The parties have grouped the 65 parcels generally into six groups.

The first group of contested parcels comprises the land for the Prairie Landing Golf Club (Golf Course Property). The Golf Course Property contains a 21-hole public golf course and appurtenant facilities, such as an 18,600-square-foot clubhouse, a maintenance building, and a pump house. The clubhouse consists of a golf shop; restaurant; bar; locker rooms; and banquet facilities for private parties, weddings, and business meetings. In the year 2000, the golf course charged $90 per round of golf (including use of a golf cart).

Plaintiff owns the golf course and appurtenant facilities.For tax year 2000, the golf course was maintained and operated by a private, for-profit management company, Meadowbrook Golf Group, Inc. (Meadowbrook), pursuant to a management agreement. The annual management fee was $85,000 plus bonus payments based on the revenue generated by the golf course.Meadowbrook also maintained and operated the clubhouse, pro shop, restaurant, and banquet hall. Except for parcels containing portions of a runway, a heliport, landing guidance lights, and a clear zone for the runway, there are no aviation or aeronautic activities occurring on the Golf Course Property. Though plaintiff did not itself maintain or operate the golf course or its facilities, but instead did so through its agent, Meadowbrook, the Golf Course Property serves as a revenue source for plaintiff.

The second category of property is the Flight Center Property. The Flight Center Property measures approximately 86.93 acres and contains the Flight Center building as well as a tie-down area for aircraft. The Flight Center building is a three-story office building containing approximately 58,280 square feet of space and having a footprint of 17,000 square feet. For tax years 2000 and 2001, all of the Flight Center Property, except for 18,966 square feet of the building, was exempt. The nonexempt 18,966 square feet was leased in 2000 to Raytheon, which used the space as office space for aircraft management and aircraft charters; Kitty Hawk Caf