In the past I have brought dogs to see fireworks with me and we all sat in the car watching them and that has worked. Last year Midnite barked at them like your dog, but only the ones that were in the sky and he didn't try to escape, but lunged at them. After a few times he stopped and laid down and watched them. I'm interested in knowing how he would do this year. I think it's a process and depending on the dog it can happen with some time.
I took my guy to a fireworks show last year because he'd shown absolutely no reaction whatsoever to hunting gunshots. The first time he saw one he leapt up and stared at it intensely, and after a few more he was pulling on the leash to escape. He ended up hiding under my legs, and then finally finding one specific firework he always had to bark at. I would have left at the beginning if we weren't stuck in a thick crowd.
If he hears a firework or firecracker from the house, he does his usual hackles/alert barking routine he reserves for other dogs barking and suspicious sounding noises outside. My female gets obviously stressed with heavy breathing and wandering around aimlessly, but he's not like that at all.
I took him outside when people were shooting off fireworks on Victoria Day here, and as soon as he gets the visual component he is much more intensely interested and then wants to get away. He was okay with sitting in the back of the car with me, but not terribly happy about it.
I won't make the mistake of taking him to another display, but I find it very interesting how differently he reacts to the same thing in the two situations. I'd definitely rather he didn't react to them as much in the house, and I think I might be able to work on it since it doesn't seem to be a fear response.