What kind of weird Yak -9s was this movie using?
Okay, even being something of a military history fan, I have to cut this movie a little slack. It's not like it was easy to come by surplus World War II Soviet fighter airplanes.
The Russian commies suppled North Korea with surplus, WWII Yakovlev-9 fighter airplanes and Ilyushin I-10 Stormovik ground attack aircraft. The Yak-9's outward silhouette and outline roughly resembles that of a British Spitfire fighter plane from the same time period. It certainly doesn't resemble the radial-engine A-10 advanced training air planes used by the United States of the same time period. It would have been better off if Hollywood could have obtained a few surplus British Hurricane fighters and dressed them up as Yaks.
The Soviet Yak-9 and the Yak-3 proved to be formidable fighter aircraft, capable of 400 mph plus speeds, and specialized in low-to-mid level altitude operations where they outperformed the German Bf-109G and even the vaunted Fw-190. The armament of, typically, two, 12.7mm heavy machine guns and one 20mm/23mm cannon was sufficient against any Axis fighter. Experienced Soviet fighter pilots could have put up a serious fight against American P-51Ds in the first three months of the Korean War, but the Yak-9s were manned by North Korean pilots who were gravely inexperienced. Not enough of the quality of their training is known to judge them on that aspect. But the gross inexperience of the North Korean pilots was their undoing against experienced American aviators flying the still hot shot P-51D fighter plane. Also the North Korean military air force was miniscule. Numbers were not on their side. Within three months of the onset of war, the North Korean air force was all but destroyed.