Anxiety in the car

Hey friends! So my boy Oliver has started to get anxious in the car. He never had issues with it until all of a sudden, with a flip of a switch, he now gets anxious in cars. He is panting and drooling along with on and off shaking. It’s not instantly but if we are in the car more than 15 minutes it seems to flare. We have tried trazadone but to no real avail. Anyone else have basset(s) with a similar issue and have a good resolution? I’d prefer to not have to heavily drug him but we like taking them on our little breakaway vacations which usually require 3-4 hour road trips. Any insight is greatly appreciated. He is 7 and the issue started prob closer to when he turned 6. He is the one eyed wonder in the photos ❤️