During WWII, Typical Aircraft were not used at Night. At least not in the Pacific, and not earlier in the War.
The Allies did use nighttime bombing, but these typically took-off and landed during the daylight hours.
There were seaplanes and Patrol Aircraft that operated at night, even earlier in the War, but again, these usually took off during daylight hours, at dusk, and then landed at Dawn.
One such example is the Seaplanes used by the Japanese in the Battle of Savo Island, or the use of the Dornier Do.17 by the Germans. The Dornier was equipped with an early example of IR detection, and carrier an IR spotlight to help illuminate targets, but it was not easily used, as the pilot was constrained to a small scope which did not have a large field of view, making it easy for enemy aircraft to maneuver away. Although they did have limited effectiveness against Night Bombing.
But the Japanese used night aircraft operations really as a nuisance and Psychological Warfare Operation, rather than as a means to attack the enemy with any results. Their ship-bease float planes, while often operating to assist night Surface Actions, were also often employed as what the Allies called Washing-Machine Charlie or Maytag Charlie (after the manufacturers of Washingmachines).
A Washing-Machine Charlie was a float-plane, sea-plane, or medium bomber (or other Twin-Engine aircraft), who the Japanese would mis-tune the engine so that it would produce a lot of noise.
The aircraft would then fly over the allied positions, randomly dropping flares and bombs, not typically meant to actually cause any damage, but rather to unnerve and disorient Marines or Pilots, who would lose sleep, and thus be less effective the next day.
In game terms, this could be seen as decreasing daylight Fighter Pilot's effectiveness (lowering their quality a level).
Also early in the War, the UK mounted early Radar sets in the Fairey Battle Light Bomber and Bristol Blenheim, and saw limited successes with it in intercepting Night Bomber formations in the earlier raids against England and France (very early in the war - but not used in large numbers until The Blitz).
The early British Airborne Radar sets had a limited Effective Range. While able to detect enemy formations at several miles, they were not accurate for aiming at ranges greater than 20,000 feet (listed as 6,000 - 7,000 yards), with a minimum range of around 400 - 500 feet (130 to 170 yards).
Slightly improved systems were used in the Beaufighter and the de Havilland Mosquito in 1940, which accompanied Bombers on Raids over Germany.
The Axis had several Nightfighters at the time as well. The Dornier, as mentioned, and the Junkers Ju 88, but these were not deployed until 1942, due to differences in Strategic Operations and Topology (how the ground layout and distances affected weapons systems).
The British, being ahead of the Germans in Radar development, also rapidly countered with Radar Jammers in early/mid-43 (several different systems were used).
The Germans also tried a Focke Wulf FW 190 and Messerschmitt BF 109g that were mounted with Radar Homing Equipment, allowing them to home in on Allied Bombing formations.
In terms of effects on the aircraft, the German Radars also slowed the aircraft by about 25 - 50mph, due to the large dipole antennae they used (why they did not create a covering for it to help avoid this problem is a pretty big question).
I suppose in Game Terms, for a formation supporting a Night Surface Action (this will vary depending upon Theatre), the Aircraft would be limited in how it could be used.
For instance, Torpedo Bombers, Dive Bombers, and Level Bombers would all have a very difficult time hitting their targets, unless the targets were illuminated by Flares or Searchlights.
Page 5-10 of the Optional Rules contains rules for Night bombing and Torpedo Attacks, which are limited to specific aircraft and times.
These include most functions for Night Operations that could be effective (other than Float-Planes dropping flares).
About the only other thing I can think of is that if Fighters are attempting to dogfight at night, they would have an increased chance of crashing at low altitudes (Level 1 or 2). I am not sure how to go about resolving that.
More specific information about what is intended in the Night Air Operations would need to be given so as to avoid creating a complete set of rules for Night Air Operations that include every possibility that might be encountered.