Not in the purest sense of "Air Taxis" but I did have an interesting experience with a chartered air shuttle service several years ago that made us think about "value," "savings," "necessary travel" and a handful of other concepts.
I was doing some work for a company that had several manufacturing facilities that were a couple of hours away from major airports so they had in place this pretty slick shuttle service that afforded all the benefits you mentioned as far as time savings. In fact it was
so slick it was amazing how full those shuttles were.
Long story short, the company and its charter service had a falling out over pricing, service levels, etc. and called the charter service's bluff and walked away (with every intention of either finding another carrier or the original carrier coming back to the table with their tail between their legs). Well a month passed...then six months...travel between sites was down somewhere around 75%...business results hadn't been effected...to my knowledge they never didn't sign with another charter service.
Now granted there are some differences...namely most of the folks moving around were what most would call "project managers" or "senior engineers" not C-Level folks...but the lesson for me, at least, is if you make travel
too easy, it is amazing how many people will travel.