Any suggestions on how to avoid these?

Thanks in advance.

If you are using braid make sure the line is not digging in. Increase the braking on your reel. If that doesn't do it, tighten the cast control. Make sure your lure is heavy enough to use with a bait caster. No one can cast a fly with a BC. Practice letting you thumb make a little friction on the spool near the end of your cast. Practice, practice, practice. I hope this is helpfull.

Ronnie

Another possibility is the line is wrapped on the spool too loose. This can happen when using plastics, or any retrieve that picks up slack line. Hold the rod/reel so you can grasp the line between your thumb and first finger. Apply a little tension when cranking. Try it, and see if it helps. This will be a little clumsy at first, but you'll get used to it.

Good luck,

GK

Most of my mid air backlashes have been caused by overspooling too much line on the reel.

All of the above people gave excellent advice.  

I occasionally get mid-air overruns from whipping the lure out insted of a smooth, steady cast.

When casting a BC, try to think of the rod as a hammer, and you are swinging it as to hit a nail.  

I don't know if that helps you, but for some reason that analogy helped me to become a little better with my 1st baitcaster.

Casting into the wind will cause that too.Your bait is casted,pulling the usual amount of line,wind catches it,slows it down and the spool over-runs.Happens all the time.

Once you fully get the hang of your reel,you'll be able to feel a backlash starting to happen with your thumb as well as hear it.Anytime you feel something weird going on,put your thumb on the spool and stop it immediately.

yes I remember how before my thumb got a bit of an edjumication I watched my birdsnests happen with that dumb look on my face like... ohhh crap that is going to take a LONG time to get out  ;D

keep on keeping on my friend ... the more you practice the better you get.. and I have a LOT more practicing to do

AL

either use more thumb or tighten the cast control.i would use more thumb.