What I presume you refer to is the idea of sub-orbital flight on which companies as SpaceX and Blue Origin are working on. It would mean that travel times would be expressed in minutes instead of hours. There surely is some development there but I didn't include them in the article for two reasons.

First of all, deploying such a technology on a big scale could make air travel more polluting, not less (depending on how the transport vehicles would be powered) while the biggest challenge for the future in aviation surely is sustainability.

Secondly, probably the most important reason, if such a mode of transport would become available, it would only be for the richest of the richest. I think chances are that something like that would end up having the same fate as the Concorde.

Of course, traditional flight also once was only for the richest and there are ways to make sub-orbital flight sustainable too by using for example liquid hydrogen (though that has its own challenges).