The 'Aerolithe' was a concept car, in effect the prototype for the Type 57 Atlantic. It used a magnesium alloy for the body, which was very light, but also rather flammable. So welding wasn't a viable option, and, alternatively, riveting was used. This required a seam across the roof, where the two halves of the car came together. Although the production Atlantic used aluminium body panels, that seam was retained and became a trademark of, first, the Atlantic, and, subsequently, most of the modern Bugatti models.
The 'Aerolithe' prototype hasn't survived, and there are only a few photographs and sketches showing what the car looked like. The colour was said to be a silvery-blue.
To the best of my knowledge, there is no commercial model of the 'Aerolithe' in 1:24 scale. Or any other scale for that matter.
But ... I did come across one listed on eBay! Turned out that this was a private customisation of the very common Bburago 1:24 model (which was the first in my collection), making it look like the 'Aerolithe' as much as possible.
Here it is!
Compare it to the photo of the 'Aerolithe' above .... I think that whoever customised this model did an excellent job, and, although it's not officially a model of the 'Aerolithe', I'm perfectly happy to add this customised model as such to the collection