It's very dangerous to do low level attack on a ground forces in good hiding, specially at priority units they deployed big chunks of 20mm's AAA defending those areas.
1rst SS corps killed scores of attack aircraft's during their campaign at Caen area, confirmed by wreckage's. Due to the difficult terrain the allied fighter bombing where not that effective, artillery however, was sending quite a fews tanks back to the rear for repair.
source "Steel Inferno"