From: The Army Air Forces In World War II

Operational training for fighter units followed the standard OTURTU pattern, but naturally differed from that of bombardment units.

Only in night fighter planes did the combat crew consist of more
than one member, and the overwhelming proportion of fighter pilots
served in the single-seater day fighters. From December 1942 through August 1945 more than 35,000 day fighter pilots were trained, as contrasted with only 485 night fighter crews.I6 Since the problem of crew teamwork did not exist in day fighter training, the program was directed toward maximum individual proficiency and precise coordination among the pilots of each squadron and group.
The instruction prescribed for the individual pilot varied considerably during the war.

Although the Training Command eventually gave some transition experience to pilots on combat fighter types, it was generally necessary for OTU’s to give transition training on whatever aircraft might be available. Following such familiarization, the pilot was required to fly the aircraft in specified acrobatic, aerial bombing, and gunnery exercises, and in simulated individual combat.

Navigation missions, instrument flying, and night flying were also prescribed. Stress was placed, especially after 1943, on high-altitude
operations and on the development of combat vigilance and aggressiveness.

Unit as well as individual instruction was limited by the
pressure of time during the first part of the war. Within the hours
available, the greatest attention was paid to take-off and assembly procedures, precision landings in quick succession, formation flying under varying conditions, and the execution of offensive and defensive tactics against air and surface forces, Along with these came instruction on how to maintain aircraft in the field, on procedures for movement to a new base, and on necessary administrative and housekeeping activities.

Night fighter training, though it had much in common with the
standard program, differed in certain important ways. Instrument flying, night formation exercises, and night gunnery had to be stressed. Attention also had to be given to crew teamwork since the night fighter was operated normally by a pilot, radio observer, and gunner.

Unit tactics were on a smaller scale than for day fighters but were
more complex and difficult. The basic operating unit was a squadron
rather than a group; its mission was the interception and destruction
of enemy bombers raiding by night.