I am coming up with too many ideas. But I think this one is actually good.

I'm particularly interested in anachronistic and erroneous aircraft in movies. Like the HA-1112's in the Battle of Britain, Harvards and Texans posing as Zeroes in every Pacific theatre war ever, the Pilatus P-2 posing as a Jabo in The Last Crusade, and the Harvard Luftwaffe in Where Eagles Dare.

The B-25 Camera Plane for Battle of Britain is also a pretty neat build.

Thoughts?

A "What If" Hollywood style!
Count me in.

I think this can be a cool idea!

Well I can add to the list (with a foray into the jet age):

All time classic MIG-28's from "Top Gun" played by black F-5's (would be my personal pick), then we have MIG-23's played by Kfir C-2 in "Iron Eagle" and MIG's (my memory maybe wrong) played by F-4's in the sequel "Iron Eagle 2".
Then one could always include totally fictional planes. I have two that spring immediately in mind: "Blue Thunder" heavily modified SA-341 Gazelle and totally fictious MIG-31 in "Firefox".

I would also suggest seeing if there is any interest also over on Armorama for a similar situation with tanks (I remember seeing some threads about movie accuracy tank-wise).

When I was a kid I lived in Saffron Walden, Essex where
"The Battle of Britain" was filmed ( months of filming for a two hour movie!).
Duxford was the RAF base and Debden the German base.
The B-25 was the main camera plane but a two seater Spitfire was also used as a camera plan.
They actualy blew up one of the wooden hangers at Duxford!
this would be frownd upon now!

You've got me thinking now!
Anyone know what the biplanes were in the 1933 version of King Kong?
Also, ever since I saw Rodan (one night last year), I'd been thinking that if I built an F-86, it would be one of the JADF planes that comically taxied around behind the conversations in the tower. I'd have to watch that again a few times.
I just watched Top Gun a few nights ago, and yeah, those black F-5's are so blatant!
I read somewhere on the interwebs that the unfamiliar planes used in "Hot Shots" were actually a British jet, but I don't remember the details. I know the planes said simply "The Navy" along the fuselage sides.
Good idea!
-Sean H.

The Hot Shots jets were Folland Gnat T.1s with missile tube openings painted on their fuel tanks.

And not forgetting the Aérospatiale SA 330 Puma that posed as a Hind in Rambo III

That would be great, but that will oblige us to (re)view all the aviation related movies from the fifties for an endless list of planes. For one, one of may favorites, “The Bridges at Toko-ri” for Panthers and HO3S-1. Or all John Wayne pictures, with “Flying Leathernecks”, among others... At the end, we will probably find time for modelling .... or we will be to old to do so ....
Cheers !

Hi:-
Dambusters.
633 Squadron.
Chitty Chitty Bang Bang (for the auto crowd).
Magnificent men and their flying machines.
Reach for the sky.
Spitfire.

depending on date I have an airwolf in the stash

How about the "Mary-Ann" from Airforce

For tanks there are the M-47 posing as King Tigers in "Battle of the Bulge", some heavily modified T-34s posing as Tigers in "Saving Private Ryan" and the same (I think) in "Kelly's Heroes".

If I had to choose I would probably build a Buffon as a Me 109 in the "Battle of Britain" movie.