Is it normal having all the hardened air shelters all in the same location? It should be an inherent vulnerability having that many high-value aircraft so close to each other
Also, shouldn't the air shelters not be connected with each other? So that the destruction of one air shelter doesn't structurally weaken or compromise the other 2 (left and right) which are connected to it.
On the other other hand you could argue that having them connected means that the impact/explosion forces can be (depends on many variables) directed nearby and thus potentially reducing the damage in the structure
Hardened shelters are by design proof against all but the largest explosive blast weapons.
To get at the aircraft parked in them, you need dedicated bunker buster deep penetration bombs.
As such, placing them right next to each other has minimal drawbacks since a bomb dropped between two shelters will not penetrate either, and a successful penetration of one shelter should not also breach any neighbouring ones.
The benefits of building them so close together makes it easier to play shell games since it would be quicker to move planes between shelters.
Such a tight pack configuration could also indicate that these are only the inner layer, and that they ultimate intend to add another layer of armour over the entire cluster of individual shelters to create one big structure.