Well... it's been a while since I did all the work on this. I've since moved on to SF2V where it's not an issue.
But I will say this, I tried everything, and I mean EVERYTHING, that I and others could think of to resolve this issue. Adding Mig Units, moving Mig units, changing supply levels and start dates for mig units, changing campaign parameters, start dates, supply levels, offensive priorities, supply levels, etc... I'm not going to rack my brain to remember everything I did - just trust me... I tried it all.
The bottom line is this:
1. Get SF2V or use the '06 WOV patch if want a properly functioning campaign.
2. If you want to use the '08 patch, you either:
a) Strike Noi Bai over and over again in campaigns with little to no A/A or,
b) Get no A/A at all in campaigns but varying strike targets.
That's just the way it is.