Oh, indeed. And the story of its origin is wonderful. In 1940 the British wanted North American Aviation to produce Curtiss P-40 Warhawks under license, but NAA thought they could make a better aircraft faster. And the first P-51 rolled out 102 days after the contract was signed, and first flew 47 days after that. It took a few years of upgrades and revsions to turn it into the best piston-engined fighter of the war, but compare that initial design and development cycle to the years and even decades it takes to get anything built these days.
Interesting tech note: the P-51's distinctive radiator/oil cooler actually added speed to the plane: cool air came in the front, and the hot air exiting the back added some jet-like thrust.