If you try to build a travel website using a standard e-commerce platform, you'll surely find out that it doesn't do the job.
Unlike a standard e-commerce solution where each item has a basic price, the travel agency's offer is more complex and the price depends on many variables such as: availability, time until traveling and seasonality.
A tailor-made website for travel agencies must display real time availabilities and prices so the travellers can book and pay without the travel agent's intervention.