I can relate to the car issue. Here's what I can offer.
It's a behavior modification process. It can take some time, but it really will work if your consistent.
Take him to the car as you normally would and note when he starts to flip out, that's where your starting point will be.
Let's say you put him on the leash and walk him to the car, put him in and shut the door, and that's when he goes crazy.
Day 1 - Take him to the car as you normally would and put him in the car. Give him a treat and sit in the drivers seat and wait a couple minutes. The instant he calms down, if even for a second, say, "good boy" pat him and give him a treat. Get out of the car and go inside. Training done!
Do this process for 7 days, painful yes, I know, but truly it works. Depending on the dog, you will see him adjust to being calm at this point because he knows he's going to be rewarded.
Day 8 - Take him to the car, put him in the car, start the car. Again, wait for him to calm and treat him, pat him, etc. Turn off the car and go inside. Repeat for another week.
Day 14 - Take him into the car, start the car, drive around the block. Wait for him to calm and treat him, etc.
The more limited exposure you can give him the better this will instill the training in the long run. If you go through it too quickly he will just go back to his normal freaking out in no time.
Now, don't do this process and then decide to go for a drive with him. Be sure to separate the training from the car rides. You will have to drive with him, I'm guessing, so when you do, let him do what he does, so he doesn't associate the training with the driving.
The basis to this is to have the dog always please the owners. He knows that he will get a treat if he does x, y, or z. So, as dogs to, he will do that to get his treat. All he realizes is if he's calm he will get a treat. It's a little backwards from training him OUT OF being a spaz in the car, rather your training him to be good in the car.
We did this when our dog had panic attacks in the house when we left. It was three months of daily training like that. From walking to the front door, to driving around the block with him alone, to eventually leaving him home for 8 hours a day! We went in increments of 5 - 10 mins weekly, so I know the pain all too well!
We were in such a state with our dog that it came down to us needing to fix it, or to give him away, there was no other options. We tried everything we knew. We threw a chunk of money at a behaviour specialist who gave us this training program and to you I give it for free!!
If you want to pm me, I'd be glad to help or explain more!