This industry comprises establishments primarily engaged in (1) operating international, national, or civil airports or public flying fields or (2) supporting airport operations (except special food services contractors), such as rental of hangar space, air traffic control services, baggage handling services, and cargo handling services. Cross-References. Establishments primarily engaged in-- ? Providing factory conversion, overhaul, and rebuilding of aircraft--are classified in Industry 33641, Aerospace Product and Parts Manufacturing; ? Wholesaling fuel at airports--are classified in Industry 424720, Petroleum and Petroleum Products Merchant Wholesalers (except Bulk Stations and Terminals); ? Providing airport janitorial services--are classified in Industry 56172, Janitorial Services; and ? Providing food services at airports on a contractual arrangement (i.e., food service contractors)--are classified in Industry 72231, Food Service Contractors.