The Aircraft Center improves Aircraft Heroes. Construction requires Base level 15, and upgrades add Aircraft Hero HP, ATK, DEF and Squad Size.
How Aircraft Hero Squad Size works
Squad Size concerns the units associated with heroes in a formation. It does not increase the number of separate marches you can deploy. That is the role of additional Squad buildings.
At Aircraft Center level 10, its bonuses are 37 Squad Size, 5,000 HP, 248 ATK and 50 DEF. Level 30 provides 100 Squad Size, 25,500 HP, 744 ATK and 150 DEF. Aircraft research has its own Squad Size improvements as well.
Bonuses follow hero type
The Aircraft Center's effects are specific to Aircraft Heroes. A mixed formation can also contain heroes supported by the Infantry Center or Tank Center.
Formation bonuses are another system. Deploying heroes of matching types can grant battle HP, ATK and DEF bonuses according to the lineup. That formation effect is separate from the permanent building bonuses described here.
