The 1953 XP-21 Firebird 1 was the first gas turbine automobile ever to be built and tested in the United States. Designed strictly as an engineering and styling exercise, Firebird 1 was intended to determine whether the gas turbine could be used as an efficient and economical powerplant for future vehicles.

The idea for Firebird 1 originated with Harley J. Earl, the legendary GM Styling Vice President, who also designed the car's aircraft-inspired fiberglass-reinforced plastic body. The engine, termed "Whirlfire Turbo-Power," was developed under the direction of Charles L. McCuen, then general manager of GM Research Laboratories Division.

Unlike a jet airplane, which develops thrust through the action of exhaust gas through a tailcone, the Whirlfire Turbo-Power engine propelled the Firebird 1 through a power turbine acting on the rear wheels via a transmission. The engine was capable of 370 hp at a power turbine speed of 13,000 rpm.