 During World War II, Piper L-4 Grasshoppers and a few larger Stinson L-5 Sentinels were used to adjust artillery fire, gather intelligence, support naval bombardment, direct bombing missions, and perform other functions.Most training of both pilots and mechanics was conducted by the Department of Air Training within the Field Artillery School at Post Field, Okla., although the Army Air Forces conducted some primary training of organic Army Aviation personnel.After the creation of the Army Air Forces, the Army Ground Forces retained the use of light aircraft for artillery forward observation and reconnaissance in June 1942.