I very highly recommend the GR mods by CENT.
They have some choppers that are flyable, mostly attack birds I believe maybe CENT will jump in here sooner or later.
TANK as always being a man of few words sounds like he has the ultimate solution, and I had to go and try it ... "cool beanz" I had to try out an FA TANK battle (no pun intended)
As to Zephyrs lib, what I do with his is run the .BAT installer (I think that is what he uses) and redirect it to my folder where I keep all my .lib and then drag and drop it or copy and paste it into FA.
I've never had any problems and just pay no attention to his readme as to the particular .lib files that aren't suppose to be there.
Here is a link to CENTURIANs site if you want to give the GAMEREMOD a try.
http://www.theforsakenoutlaw.com/main.htmI can't say this enough times ...
It is a very good ideal to extract .libs for this game into a different folder, and then drop them into FA. The reason I felt like I had to renter ate this is that you are trying to use ZEPHYRs .lib and I think it has and installer.
Very few user made .libs will work in conjunction with others so only one .lib at a time. If you manually drop stuff into the FA directory then you have a better ideal of what is in there so if it craps out you know what the heck is doing it.
And here is another "cool beanz" tip ... again from TANK some time ago.
You can make as many folders in the JANES directory as you want I.E FA2, FA3, FA4, call them whatever ....
Then just copy and paste the entire Fighters Anthology into them.
This was one of the coolest tips I ever got here, and right now I have a stock install of FA in the default location for online play, I got an GR one, and ZEPHYRs lib in another, and still one more with CAGs Korea remake. This way I can work on missions with which ever .lib and never worry about conflicts and or mix ups if I forget which freakin mission goes for what .lib