Car Ferry flights
I do remember taking my car, an early Mini, to the Continent via Lydd on a Bristol Superfreighter, I guess it would have been in the very early 60's. A very noisy and low level flight I seem to remember.
I seem to think that the price at that time was not so different from that of the fare by boat. (maybe they were doing deals on the air fares then, but I doubt it...)
As to insurance, we had the infamous Green Card which was essential as well as a tryptique for the car.
Mike