Leitra is a Danish company and also the name of the velomobile it makes. In Sweden a design for two persons called Fantom was sold as blueprints in the 1930s and 40s. Many thousands of DIY instructions were sold, but very few were actually built. The body was made of plywood. The second oil crisis in 1978 inspired Carl Georg Rasmussen, a Danish engineer and pilot, to design and build the first practical velomobile. It was called Leitra (Leight individual transport), a tadpole recumbent trike with full glassfiber fairing. It was tested in the 1980s in several tough rallies like Trondheim-Oslo and Paris-Brest-Paris.
See the web-page : Leitra Or if it should become unavailable the web.archive.org copies.