Complex sentence: After a short posting back to 1 Squadron, Elkington joined No.539 Squadron RAF flying the Havoc aircraft and then on to No.197 Squadron RAF at RAF Drem flying the Hawker Typhoon aircraft.
Split into simpler sentences: After a short posting back to 1 Squadron, Elkington joined No.539 Squadron RAF flying the Havoc aircraft. He then joined No.197 Squadron RAF at RAF Drem flying the Hawker Typhoon aircraft.