Although Plymouth enthusiasts insist that the Baracuda beat the Ford Mustang to market by two weeks, the Mustang is generally considered the first "pony car", a new class of automobile first introduced in 1964 and designed to be more compact and more affordable than the larger muscle cars that inspired them. It was the Ford Mustang, first introduced at the New York World's Fair on April 17, 1964, that captured the imagination of the American public and guaranteed the success of the pony car. In fact, the Mustang was perhaps the most successful product launch in automotive history. Racking up over 22,000 sales in its first day and one million sales in its first two years, the Mustang inspired a wave of imitators including the Pontiac Firebird, Mercury Cougar and Chevrolet Camaro, but none could match the success enjoyed by the Mustang. Originally named for the P-51 Mustang, a fighter plane, Ford's new car quickly became associated with the horse of the same name and this became the basis for the now-famous Mustang emblem. Early versions of the Ford Mustang are highly collectible today.