After designing the first online travel reservations engine in 1997, I left the travel industry. But there is still something left to do. Trip planning is still focused on using a form to search flights. We haven't been able to replace the travel agent, we just forgot how nice it was to have that kind of service.
The next stage of travel support should be the development of (1) an itinerary-based query system that enables a user to describe the trip they want and (2) to be shown results based on "travel agent" logic on (3) their own calendar. Come on, Sabre. Let's do it. I still have my notes.