I bought this one from Cal-Orchid and it is/came potted in a bark mix. I have it hanging in the greenhouse and have not repotted it since I bought it a couple years ago. However, since then, it has put out many aerial roots that hang freely. When the roots are even 6 inches or so they are still unbendable and were unable to get them in the pot. You can see a couple in the photo.
However, a tiny tidbit I have observed regarding Aerangis. They ALL love to be mounted, and most must be mounted(at least in my growing conditions.) I have over 80 Aerangis plants (31 different species,) many imported from Africa, and they do MUCH better mounted. If one is sulking in a pot, by mounting it I usually get root growth very shortly thereafter.
It was Aergs. ellisii that got me hooked on this genera and this hybrid looks very much like ellisii and is more vigorous.