Complex sentence: On the 1 April 1918 the Royal Flying Corps became the Royal Air Force, and Upavon became Royal Air Force Upavon, commonly abreviated to RAF Upavon, and the former Army Central Flying School became Royal Air Force Central Flying School.
Split into simpler sentences: On the 1 April 1918 the Royal Flying Corps became the Royal Air Force, and Upavon became Royal Air Force Station Upavon, commonly abreviated to RAF Upavon. Accordingly, the former Army Central Flying School became Royal Air Force Central Flying School.