So the addon needs to be updated. Is the original author no longer doing this? Probably a dumb question, sorry. But I don't see why someone hasn't resurrected this great addon. I would do it myself but I've got zero experience in coding such a thing and don't have the time to learn. I'm only able to play WoW maybe 3 hours per day.
Since the issues posted above your thread were fixed in the latest build, InFlight does not need to be updated; it works as intended right now.