Why is Aflatoxin banned? It may be a spell which can create creatures, but it requires a creature already there to do so. It's more akin to Mutation in that it modifies a creature, as opposed to Boneyard which creates one.
so a flying weapon deck is also a no-go
Correct. Flying/Animate Weapon are both allowed, but because all weapons are Permanents you would not be allowed to use spells, such as Flying/Animate Weapon.