Complex sentence: Beeson planned to join the Army Air Corps as a pilot, but as he had not completed the required two years of college he joined the Royal Canadian Air Force in Canada, which had no such entry qualifications.
Split into simpler sentences: Beeson planned to join the Army Air Corps as a pilot although he had not completed the requirement of two years' of college. Thus he joined the Royal Canadian Air Force in Canada, which had no such entry qualifications.