The four horseman of Armageddon, the US deep state!, page-11

The Russians like the US have several what you would call Airforce's.
They could fly a whole air wing of high altitude bombers in and carpet bomb the whole area if they so wanted.

Being of a military background I would say the bombing may have stopped in Idlib because their ground forces are going in or about to have a big push. Normal for artillery and air support to stop when the ground forces go in. Also in the event of a Nuclear strike you will see forces withdrawn suddenly to a safe distance.