ORIGINAL: STEF78
Good idea but I have no more fighters groups with BF110
You do have them in the pool - so you can swap them to that, as in your example above, and then onwards to single seat fighters. Each swap does mean a loss of experience - but it way be worth going through a chain of swaps where the end of the path is a single seat fighter group if that is a choke point.
There are quite a few aircraft types that exist in airgroups or the pool but for which there are no factories. So in v.1.10 8/NKG 200 arrives as an airgroup equipped with FW 190A-5/U2 night fighters on turn 113 but there seems to be no factory for them. I have always assumed this were the small numbers of aircraft produced as a test run or for demonstration which remained in the Luftwaffe but were never commissioned for mass production - but I guess the developers will have to explain.ORIGINAL: STEF78
Concerning night fighters, what I can do, see below