The 1958 Firebird III was General Motors' most advanced concept car, blending jet-fighter styling with Space Age technology. Designed by Harley Earl, it featured a fiberglass body with seven fins and a double-bubble canopy. Inside, a joystick replaced the steering wheel and pedals to control steering, acceleration, and braking. It utilized a dual-engine system: a rear gas turbine for propulsion and a front gasoline engine for accessories. This "laboratory on wheels" introduced innovations like cruise control and anti-lock brakes, while its bold aesthetics directly influenced future Cadillac production designs.