Vertibirds would be pre-war. I doubt the Enclave would set up bases for them like the one in New Vegas in advance of actually having a vertibirds. I guess it has to be put down to artistic licence for the way they look.
I would not call it a Fallout 3 mystery so much as a Fallout 3 canon/logic mess up. Logic and evidence would show Vertibirds are pre-war. Enclave had them stashed in Fallout 3. They could have the ability to build them but not in the numbers seen in Fallout 3 and in only 30-35 years.
Things may have been scaled down in Fallout 2 but the impression was that they were not a very large faction. A very powerful one yes but not in large numebers. Navarro Only had the two Vertibirds. The Oil Rig could have had alot more but they went up in the blast.
What ever it was that said it was to be built in 2085 could just go down as another type of vertibird. Vertibird 2.0 if you will.
Of course they are old sport, nothing has disputed that; I see no reason why the Enclave wouldn't have built an infastructure pre-war whilst they still had the capability, we are operating on the assumption that they stockpiled Vertibirds for post-war use? Then it only makes sense for the Remnan's Bunkerto be apart of that plan surely.
The massive numbers of
anything Enclave in F3 deserves a topic all on it's own, not here, we've discussed it before though and no reasonable conclusion based on previous evidence can be garnered in my opinion; I find it pleasing though that it was F3 itself that shot itself in the canonical foot so we can't be hit with the old, "Fallout Dinosaurs, old [censored] forgotten, who cares," arguement.
It was a display at the Technology Muesum in D.C. beside a model of F3's Vertibird, I suppose it could be rendered as simply incorrect infomation as it is a public display.
@Dustin, indeed it was.
@Andius, that is what the Vault says but I refuse to believe that the Enclave produced an entirely new fleet at Raven Rock, they are not refered to as different and are merely artistic licence in my opinoin.