Ok, so I think I had a bit of a bass epiphany the other day. I’m hoping maybe this might help someone else in a similar situation.
Though I’m more of an intermediate player according to @JoshFossgreen’s checklist, I’ve been going through the B2B course to work on my fundamentals and focus on developing better technique. One of my main concerns has been curing my flying fingers. Well, it’s really only one finger at this point. I’m looking at you, big bird. 
I haven’t really done much to address this other than trying to focus on it while playing, and trying to minimize or eliminate flipping the room off when I notice it happening.
Just by being aware, I’ve noticed it is happening a little less often. But the past week or so, I started seeing real progress, and that’s when the lightning bolt hit. I now realize I have one man to thank for this–Elvis Presley (and Josh, of course).
As has been pointed out at least a few times elsewhere on this forum, one of the causes of flying fingers seems to be a lack of independence and flexibility of the fingers, especially the ring and middle finger, which for most of us are used to moving together. And indeed, it’s when I’m fretting with my pinky that I find myself giving the middle finger salute.
This has also been pointed out, but I want to say it again here: this issue tends to resolve itself over time and practice if we are mindful of it and trying to use good technique.
I’ve started learning the 50 songs, starting with the “level 1” songs. I have found, that for me at least, one of the most challenging of the level 1 songs is “Hound Dog” by Elvis Presley.
For those who haven’t played it yet, or who need a reminder, the entire song is a major triad arpeggio (root, 3, 5 of the major scale). You play the whole thing using the major scale pattern Josh taught us, starting with the middle finger on the root note. For the majority of the song you’re playing this with the middle finger on the third fret, one finger per fret. So you’re on the part of the neck with the most stretch, and you’re fretting middle, index, pinky, one finger per fret, the entire song.
Just playing this song on the regular for the past week or so, I’ve seen a marked improvement on my flying fingers.
So if you’re like me and wanting to fix flying fingers, and you’re looking for some kind of drill or exercise that you can do to work on it, I humbly suggest “Hound Dog” seems to a perfect exercise. It’s also a really fun song to play, IMO.
I have slightly large man hands, but it’s a a challenging stretch for me at this point in my playing. I can make it, but just barely, and it gets harder as I get more tired.
If you have smaller hands, then it might be too much of a stretch for you to be comfortable with at this point. You could always play the song higher up on the neck where it’s more comfortable for you (you just wouldn’t be able to play along with the recording, because you’d be in a different key).
I think any song where you play the major triad pattern low enough on the neck to be a stretch for you would work.
(Edited for clarity & tone.)
I will keep these tips in mind.
