My family and I are the owners of a Cav and hes about 8 now.
Let me start this off by saying that Ziggy (our cav) has no issues with being left in the house or even a holiday home he has never been to. (We go to random holiday cottages every year and have never had an issue with him in them)
But, for some reason, whenever we take him out to any public place in the car, he starts to cry. When a member of the family gets out of the car he goes crazy. Literarily barking non stop and rapidly while jumping round the car. We are aware that we shouldn't reassure the anxiety so we leave the car as calmly as possible without paying him any attention but he still does it. Its really strange as he only gets issues when he is left in the car.

Otherwise, hes a very typical laid back cav! But im not very sure why he has an issue with the car... Any ideas on some tips to stop this?

There are a few things that could have triggered Ziggys separation anxiety. He was the last of the litter. Maybe its associated with seeing all of his brothers and sisters leaving and him being last?
It also could have been a sibling. My sibling went through a pretty bad breakdown and would always be stressed before arriving anywhere in the car. So... Maybe the nervous energy transmitted to Ziggy and gave him some sort of Separation Anxiety? It still happens wether or not he is without my sibling though.
We love him to bits and it would be great to take him to more places without him making such a scene in the car.
Any ideas on how to help him with this?
Other then this issue, he has no other issues what so ever and he is very well behaved! Its definitely a nerve thing.

Thanks everyone