Hallo Tom131, and welcome to The Cellar.
Forgive me for not getting back to you sooner but it's been something of a busy day.
When I made my initial enquiry to the US National Archives back in 1991, I gave an outline of the geographic area I was interested in, and specific locations within that area which included RAF Halton.
The Archive detailed the information it had on the station and how it was filed, ie National Archives Collection of Foreign Records Seized (Record Group 242) Target Dossiers, British Isles: GB1093.
I was invited to place an order for a copy of the aerial photo and copies of the rest of the dossier which I duly did.
It was a rather slow process back then but now much of the material held is catalogued on the
US National Archives website.
Contents of Record Group 242 are set out here:
National Archives Collection of Foreign Records Seized
Scroll down to '242.9.4 Other air force records' and see the second paragraph. You might have to dig around a bit and use some imaginative search terms, but there's every chance that there is something of use to you.
Back on this side of the Atlantic, are you aware of the collection of aerial photos held by
Historic England at their premises in Swindon?
It goes back to the early years of the 20th Century and you may find it worth investigating. The collection holds the entire aerial survey of the country carried out in 1947 by the RAF on behalf of the Ordnance Survey.
I hope that you'll find something of use to you in your research. If I think of anything else I'll post it here or PM you.
If there's anything else I can help you with, please ask and I'll do my best.
Carruthers.