The Messerschmitt was indeed a wingless plane. The two passengers sat in tandem astride a longitudinal bench seat and the steering was accomplished by means of an aircraft style bow shaped “steering bar”. Entry and exit was achieved by opening the hinged glass lid and clambering over the side. Very undignified for one’s lady friends when they were wearing their summer ‘frocks!
The Isetta certainly did have a reverse gear (I owned one very briefly, having, I thought anyway, graduated from my Lambretta SX200). The gearchange was on the offside “wall” of the car and was not very well designed. The flaw in its design meant that you could accidentally slip into reverse whilst going forward at a goodly rate. (Despite the maker’s claims of 50mph plus, about 23mph was the top speed as I remember, unless it was downhill with a stiff breeze behind you!). Access was, as mentioned, via a fully opening front door and the steering column, which was attached to the door, had universal joints which enabled it to swing outwards as the door was opened.
I got rid of mine after about three months and bought a much better Berkeley T60 three wheeler. Much better car, fibre-glass body, front like a miniature E-Type with glazed headlight recesses, twin cylinder 328cc air cooled engine, and genuine 50mph cruising speed. Superb road holding for a three wheeler. I only got rid of mine following a nasty incident when the offside front wheel fell off as I was cruising down my local high street. (The split pin holding the castellated wheel bearing nut had sheared and allowed the nut to work loose). No damage to me or anybody else but my street cred was destroyed!
By then I had passed my car test (you could drive three wheelers on a ‘bike licence) and so came to an end my career on three wheels.