Entities will sink 1 block down, into the aercloud; items will do the same. If you fall onto the aercloud without a block underneath it, unless another aercloud, you and all other entities will not take fall damage.
Methods to obtain this Aercloud
There are currently only 2 ways to obtain this aercloud without creative or op privileges.
1. Exchanging 10 VotePoints for 32 of the cloud at /warp voteshop.
2. A common/uncommon drop from one of the new Boss Fights.