Another PC in a new campaign is an Aarakocra druid, with a (wooden) shield and a free hand for spellcasting (or throwing javelins). At first, the DM and some PCs (myself included) thought the wings and arms were the same limbs. This would mean the druid could not carry a shield while flying. However, most imagery online (and in the books) clearly show they are different limbs: a set of humanoid arms, and a pair of wings on their back. So the ruling of the DM was simple: he allowed to use the shield and other weaponry while flying.
I'm fine with this ruling, but I'm still curious whether the rules say something about flying PCs that carry and use weaponry mid-air, such as a shield in this case. Is our DM's ruling correct, by RAW?