Respectfully, I think you're wrong.
Admittedly, my source is Wikipedia, but the evolution of Republic Aviation appears to be:
1965 -> Republic Aviation bought by Fairchild-Hiller
1971 -> Name change to Fairchild Industries
1996 -> Name change to Fairchild-Dornier (Oops, I guess that means no Dornier products!
)
After 1996 -> Name changed to Fairchild Aerospace
1999 -> Fairchild Aerospace purchased by Allianz A.G. and Clayton, Dubilier & Rice Inc. Bankruptcy ensues
2003 -> Remaining assets of Fairchild Aerospace purchased by M7.
2010 -> M7 purchased by Ebit Systems.
At no point in time was Republic ever under the control of Northrop-Grumman, nor do N-G or Republic appear to have cooperated in the past. About the only place where they might have overlapped is in modernization of the A-10 Thunderbolt II, and that's well beyond the scope of IL2!
But, you might be right, since fans haven't seen the exact wording of the consent decree. If the consent decree required Oleg Maddox to get the words "I love Northrop-Grumman!" tattooed on his forehead, and he agreed to do it, he'd be legally bound to do so, regardless of the logic and justice of such an action. So, if N-G told 1c/Ubisoft "No aircraft produced by Republic" in the consent decree, we'd be screwed.