Just to follow up the other posts on the cost of the service, I have found the 1955 timetable and the fares had gone up. A mid size car was now £12 10s single and a passenger £2 5s to Calais but £2 10s to Le Touquet.
A bike was 2s 6d !! There were services every 30 minutes to Le Touquet and "frequent" to Calais. Flying time to both was advertised as 20 minutes. The USP was that at worst you would be behind a maximum of 2 cars on Customs clearance as opposed to the mob at the Ferry terminal. On reflection I think that was the reason my father chose the air ferry as on a previous trip in 1950 our car was actually craned on and off the boat. Pretty time consuming compared with the Bristol Frightener.