I'm most keen on advice on the "best" website to book 1-2 seats on an existing charter. The companies listed in the articles mostly require membership fees or booking an entire plane. Jumpseat was described as the Airbnb of private jet travel, where you can book an available seat on a private jet flight, but I wasn't able to find current deals on its website, and the phone number on the site doesn't work.
No miles, true, but it sounds like a quicker, smoother, nicer travel experience that I'd like to try.