1. Airlines
   1. International Airlines
   2. Regional Airlines
   3. Domestics Airlines
   4. Low Cost Carriers
2. Airports
   1. International
   2. Domestic
   3. City Airport
   4. Rural Airstrip
   5. Navigation and Weather
   6. Low Cost Carrier Terminal
3. General Aviation
   1. Private Jets
   2. Business Jets
   3. Flying School
   4. Aerial Services
4. Air Cargo
   1. Air Cargo Carriers
   2. Freight Services
   3. Air Cargo Terminal Services