The Germans
Near the end of the war the Germans had pilots that were only 14 years old. Long ago I knew a man in my home town who flew several missions in an ME-109 for the Luftwaffe at 14. Once combat would commence he would duck into a cloud empty his guns of ammunition and return to base. When he saw that the allies lines were well inside Germany he ditched his plane behind the American lines in a field, changed back into kid clothes and was immediately was sent to the US as an orphan.
In JR High School in the US he saw American kids playing with model P-51's and ME 109's but he could not tell anyone of his story about flying a real one for fear of being sent to a prisoner of war camp.
Skyhigh