From Wikipedia: Stages of Army Pilot Training: Army Air Forces Training Command

Pre-Flight stage taught the mechanics and physics of flight and required the cadets to pass courses in mathematics and the hard sciences. Then the cadets were taught to apply their knowledge practically by teaching them aeronautics, deflection shooting, and thinking in three dimensions. Typically, cadets reported to a preflight school at the San Antonio Aviation Cadet Center; Maxwell Field, Alabama, or Santa Ana Army Air Base, California.^[1]

From Wikipedia: Aviation Cadet Training

After the attack on Pearl Harbor and the United States’ entry into the war, the number of volunteers for pilot training was enormous. Fearing that they would lose them to the general draft, aviation cadet-applicants were given exemption from 1942 until the demand lessened in July, 1944.

Demand for pilots meant that training had to be modified to accommodate the large numbers of pilot candidates. Training came in four stages (extended to five stages in April 1942 with the creation of the pre-flight stage).^[13]Classification lasted one week and the education and training stages were nine weeks each. Each 9 week stage was divided into two 4.5 week (63 day) halves: a lower half and an upper half . The lower half was made up of students just beginning the stage and the upper half was made up of the students who were half-finished. The more experienced cadets would hopefully help the new cadets get through the section before they were promoted to the next stage.

• On-line Training was the term for busy work given to cadets when there were no open spaces in the next level. They did any unskilled menial task that needed doing until a billet opened up.

• Classification stage processed the cadet and issued him his equipment. This was the stage where it would be decided whether the cadet would train as a navigator, bombardier, or pilot. Candidates who failed the testing or the advanced physical were returned to the regular Army.

• Pre-flight stage was divided into two parts and was attended by pilots, navigators, and bombardiers. The first six weeks was a compressed “boot camp” that concentrated on athletics and military training. This was followed by four weeks of academics. They were taught the mechanics and physics of flight and required the cadets to pass refresher courses in mathematics and physics. Then the cadets were taught to apply their knowledge practically by teaching them aeronautics, deflection shooting, and thinking in three dimensions. Cadets were evaluated for 10 hours in a crude flight simulator called a “blue box”, then performed a harrowing “ride-along” with a pilot-instructor for an hour. Those that passed were given Cadet Wings and were promoted to Pilot School.