aircraft to operate well at night should have to research the advanced tech on air radar.
This tech should be fleshed out a bit more and split up into a couple techs inc night fighters
and night bombing
It already does. Each level of aircraft search RADAR adds +10% to aircraft fighting efficiency at night. This stacks with RADAR combat impact from ground based RADAR stations, so if your planes are running night missions inside their own RADAR coverage, you can substantially mitigate the night penalty (which is -50% right off the bat).
Hypothetically, you could reduce that night penalty to nothing if you could afford to research enough air search RADAR enough ahead of time (level 5 would be at 1946 techs I think). That's pretty damn good for WWII techs.
Even better, navigation RADAR gives all aircraft that research it better detection against all surface targets. CAGs and NAVs with navigation RADAR are really good at finding enemy ships. You aren't hiding your ships from CAGs or NAVs with RADAR, and night time ain't going to save you, either.
How much more impact should RADAR techs have on night fighting?