Hi Larry
If you compare the aerial phototgraph of Tours-sur-Marne/Athis from 15th August 1944 to Google satellite you will find that the location of fields, woods etc today is surprisingly similar. By the way, the aerial photo is orientated West at the top and north at the right. The long straight line running top tobottom is the railway line.
Tours-sur-Marne/Athis is bordered by dense woodland on its northern edge. Things have not changed much. However, in 1944 there are some tracks into the woodland which do not exist today. I assume they were service roads of some kind - for example, to aircraft dispersal points in the woodland.
So, for exactly the reasons you give, Tours-sur-Marne/Athis airfield was probably built as either an alternative to Pivot or as a dispersal field for Plivot. The Vraux museum curator says that Plivot was not used by the Luftwaffe because Plivot was, and still is, located in open farmland where it's difficult to conceal aircraft from those pesky Mustangs. In comparison, Tours-sur-Marne/Athis was bordered by woodland where aircraft and materiel could be better concealed.
Now, just to really confuse things even further. Last night I started looking again at the Ultra decrypts. A signal to II./Jg 3 on the 17th August mentions Tours-sur-Marne; the same signal copied to III./Jg 3 mentions Pocancy. The signal is about evacuating stores - presumably as part of the transfer to the Reich. There is another related signal the following day. What do you make of these? [ATTACH]
Attachment 7955[/ATTACH]
Chris