Not quite the same. Normal trailers pivot around centrally mounted axles. Cars being ‘flat towed’ do not. They behave like normal cars.
They are attached to the towing vehicle by an A frame, rather than just a normal tow hitch.
Each ‘bottom’ of the ‘A’ attaches to the towed vehicle at either side, and the ‘point’ of the ‘A’ attaches to the towbar of the towing vehicle as would a normal trailer. With the towed car attached at two points, its direction is therefore dictated by the towing vehicle – basically the car has to go where it’s pulled because it can’t go anywhere else.
The geometry that makes any car’s steering self centre (castor angle) is what allows the car to track faithfully. The wheels will point wherever they need and nowhere else.
Doesn’t work in reverse, as castor is only there going forward – note how your steering doesn’t self centre when you’re reversing (unless you have a Citroen SM).
And you have to make sure the keys are in the ignition so the steering lock is off, or horrible things will happen. Interesting horror stories about what can happen when it goes wrong…