Many people today are booking flights for others, be it families, business leaders, or traditional travel agents. They’re communicating preferences and asking about preferred travel times, budget, seat selection, and more. When you book for and with someone else, these preferences get learned and you no longer have to ask if they prefer an aisle seat—you just pick it.

The booking experience today is granular to help you find a suitable flight to meet all the preferences you’re compiling into an optimal scenario. The experience of AI booking in the future will likely be similar: find that optimal scenario for you once you’re able to articulate your preferences and remember them over time.

More than enough. Corporate flights are almost always handled that way, alone for compliance reasons (the travel agency knows about budget and "appearance" limits aka only c-level gets business class, everyone else gets economy).

Anecdata: last year my wife and I went on a rail tour through Eastern Europe and god, I wish we had chosen to spend a few hundred euros on a travel agency in retrospect - I can't count just how much time we had to spend researching on what kind of rail, bus and public transit tickets you need on which leg, how to create accounts, set up payment and godknowswhat else. Easily took us two days worth of work and about two dozens individual payment transactions. A professional travel agency can do all the booking via Sabre, Amadeus or whatever...

not how many, but which ones? As a regular person, I buy it myself, but do you think rich people do that? No, they just ask their (human) assistant to get a flight to New York around 7pm this Friday, and then move onto the next problem in their lives.