4581 Airports, Flying Fields, and Airport Terminal Services
Establishments primarily engaged in operating and maintaining airports and flying fields;
- Air traffic control, except government
- Aircraft cleaning and janitorial service
- Aircraft servicing and repairing, except on a factory basis
- Aircraft storage at airports
- Aircraft upholstery repair
- Airfreight handling at airports
- Airport hangar rental
- Airport leasing, if operating airport
- Airport terminal services
- Airports
- Flying fields, except those maintained by aviation clubs
- Hangar operation

