Customers seek to know the best way of getting from an origin to a destination on a transportation system. Knowing the best way, i.e., itinerary planning, becomes all the more important when there are varied choices depending on the desired starting day and time at the origin or a required arrival day and time at the destination. Other considerations like cost, number of connections, etc., also play a role in the planning of an itinerary. A computer based system could enhance a customer's ability to make better choices in itinerary planning. No such system exists in either the Airlines, Railways, or Road Transport Corporations in India. This paper describes an interactive PC – based computer system developed by the authors, for itinerary planning on airlines (Indian Airlines and Vayudoot). The paper is supplemented by four annexures to facilitate further development covering system flow charts, structure of the database for maintenance and the implementation of the shortest and the k-shortest path algorithms. A users manual for the package is also provided.