I can remember players asking for this feature ever since connected flight paths were introduced back in patch 1.10. Sometimes you click the wrong flight path, sometimes you fly over something interesting and just want to get off early. Whatever the reason, in patch 6.1 you can now request a stop at the next available flight point on your route.
It's as simple as clicking the little vehicle eject button that you normally use to exit vehicles or multi-passenger mounts. Currently, once this is toggled on you cannot cancel your request to land early. Aside from that little quirk, it's a welcome feature. Now if only I could bail out of flight paths with a parachute.