Complex sentence: The squadron conducted summer training annually at Pine Camp, New York during the years 1921-40 where it generally supported the training of the 52nd Field Artillery Brigade, and other flying training most years at Miller Field and at Mitchel Field on Long Island.
Split into simpler sentences: The squadron conducted summer training at Pine Camp, NY, 1921-40 where it generally supported the training of the 52nd Field Artillery Brigade. Conducted annual summer training most years at Miller Field and at Mitchel Field on Long Island.