Travel planning is dramatically underdeveloped
There are hundreds of websites for travel services. None leverage modern technology for the benefit of the traveler. The market is highly fragmented with no client focus.
While there is a clear customer journey for trip planning, all functions work outside the normal flow separate from the other functions.
By way of example, a vegan person needs to repeat said preference to every function; for flight reservations, hotel and restaurant bookings etc.
In this era where machines work on the same global internet grid and all such personal information is provided by consent, it is unfathomable that no central management exists that will automatically and seamlessly reserve everything based on personal prefrences for that individual.