Back in 2010, Portuguese industrial designer Nuno Teixeira first conceived of the ultra-aerodynamic Pluma Track Bike. After existing purely in concept form for several years, it has now actually been built for a Geneva-based client. As can be seen, the end result is definitely not the sort of thing you come across every day.
Development of the Pluma (Portuguese for "feather") took a year, with final construction being done by French company Constellation Composite. Given that the bike is made for track racing, it has no brakes and just a single 51 x 15 fixed gear.
Its fairing consists of a PVC foam core, sandwiched between outer layers of carbon fiber. The back end of that fairing can be removed, to access the rear wheel and adjust the chain tension. That wheel (even though it's enclosed) takes the form of a PRO Track Carbon Disc, to minimize drag within the fairing.
Besides offering an aerodynamic advantage, the Pluma's unique design is also intended to protect the rider from the drivetrain and the spinning rear wheel in the event of a crash – something that happens not infrequently in the world of track racing.
Source: Nuno Teixeira Industrial Design Studio via designboom