Complex sentence: It first flew 11th September 1943 but was cancelled later the same year from showing hardly any improvments over the Me 210, it was only the Messerschmitt Me 410 that showed improvment over the Me 210 that it was put into production.
Split into simpler sentences: It first flew 11th September 1943 but was cancelled later the same year from showing hardly any improvments over the Me 210. It was only the Messerschmitt Me 410 that showed improvment over the Me 210 that it was put into production.