Oh goodness me!
A happy doggie who is embarassing to have around!
Your post made me laugh (I can just picture it!)....but at the same time I completely understand how awful this is. It's not funny!
I had a really 'easy dog', who actually made little noise, and did everything so perfectly, it seemed she'd been parachuted in from Heaven....so I have to admit I don't have much experience with training a dog to 'do the right thing'.
I do hope someone else comments who has more hands-on experience.
But my first thought is the 'reward good'positive behaviour' thing. So if, in the midst of all this noise, she ever does go quiet for a moment, praise her and slip her a tiny treat (keep a pocketful) And NEVER treat her when she is making the noise. Don't give her any attention, any words or a single thing when she makes the noise, but attention, praise, treat -when she doesn't.
If you can work on this at home first it might help. Are there istances at home when it happens? Such as when you return home after being out? Or any other instances? That might give you training opportunities which may be easier to work with than when you are on a trip/hike etc.
Well I am not the behaviour expert around here. Hopefully someone else will have a solution!
But I can relate. We have a "dog friend" (a neighbour's dog who comes around here often) He barks with excitement when he sees us and his voice is so loud it splits my ears! If I put him in the car to drive both dogs up to the woods, he makes loud moaning whining sounds with excitement, and also barks. In the confines of the car that is TOO loud!
So the only thing I have found to do that helps the situation somewhat is -(before we drive off, and certainly not while actually driving) -I clap my hands once loudly and at the same time say "No!" in a quick, commanding, sharp way. He shuts up. I then reach back and gently stroke his ears as soon as he is quiet, saying "good boy". Very often he will do it again however, and I have to repeat the whole thing. But I don't say anything else to him during this time, as I have noticed if I do, he will start making the noises straight away.
This usually does the trick -enough to calm him down so I can drive off.