The big Vercors build-up came after the introoduction of compulsory labour service late in 1943, after the Germans had occupied all of France. It was people evading this who made up much of the rural Maquis. It was really only in 1944 that the Germans began to appreciate that they couldn’t leave it to the Vichy police and paramilitaries to deal with.
The bulk of the air actions against the Vercors in Summer 1944 were by KG 26, JGr. 200, III./SG 4 and
Geschwader Bongart. There had been ad hoc air action against the Glières Maquis in March by He 111s of IV./KG 55 and Fw 190s of 10./ZG 1. Before that it’s quite possible that Army or SS units used light aircraft on spotter duties — many HQs had a small duty/liaison flight at their disposal.