Agents :

Retail Retailers who contract as Wholesalers
Corporate Retailers
General Sales Agents
Inbound Wholesalers
Outbound Wholesalers
Central Reservation Offices
Air Ticket Consolidators

Principals :

Tour Operators
Car Rental/Motor Home Rental
Hotels, Motels etc
Airlines (Scheduled)
Cruise Companies
Railways
Ferry Operators

Information Transfer Services :

BSP (Bank Settlement Plan)
Airline Clearing Houses
Land Clearing Houses
Global Distribution Systems

Other Related Segments :

MICE (Meetings, Incentives, Conventions, Events)
Tourism Information Offices