Dominant in the air is redundant in our side because the defensive midfielder is the one who contests long balls with the forward, Pep made that change after the massive Everton loss in 2017. The defensive mid challenges the striker, and the 2 CB's drop off to pick up any runners trying to pick up a flicked on header or knock down.
The number of incidents where a City CB has to actually challenge a CB in the air to stop a goal is miniscule. We almost never concede from corners, and Aké is actually like Otamendi, better than a lot of CB's 3 inches taller.