In May 1951, racecar driver Wilbur Shaw tested a batch of cars that—in contrast to the veritable barges trendy at the time—were billed as "little." They were cheap to purchase and drive. "You get what you pay for, and no more," was Shaw's assessment of the Henry J (in blue), which cost $1,360—about $12,500 in today's dollars. It lacked such amenities as a trunk door (penny-pinching owners would need to fold down the rear seats to retrieve their luggage). The pioneering compact car didn't sell, and Kaiser-Frazier manufactured it for only a few years. Though smaller cars did start finding favor in the 1970s, few of today's models are so light: At 2,300 pounds, the Henry J weighed about as much as a Fiat 500. But with U.S. fuel-efficiency requirements rising to 54.5 miles per gallon in 2025 (from 34.1 today), cars need to get lighter again, and quickly. Carbon fiber and 3D printing might help automakers get there.