Complex sentence: His abilities were quickly noticed, and he was elevated into a number of high positions eventually being placed in charge of the school's maintenance department; he remained with the school until 1944, and then spent two years on active duty with the US Air Force.
Split into simpler sentences: His abilities were quickly noticed, and he was subsequently promoted to supervise the school's maintenance department. He remained with the school until 1944, and then spent two years on active duty with the US Air Force.