An interesting fact about the air war during the "Korean Police Action" as it was called at the time. Russian pilots flew many missions for the North Koreans.
They flew in Migs with N. Korean insignia, and even made the attempt to speak Korean over their radios. After a while though it was an open secret. Both side knew the game, and what was up.
If you listen carefully you can hear the Mig pilot speak in Russian for a few seconds during this simulated engagement.
(Btw...both the American F-86, and the Russian Mig-15 were both based on the same German WW2 jet design. What would we have done with the "Krauts"? It was also 'their' scientists that put Russia's Sputnik in orbit, and later got us to the Moon.)
...more irony for ya.