He's launching, then going into Fly > jH, Unfly, M,H, ADDF, jDH, > Relaunch. There's no aerial prior.
I've been trying it on Spencer and other normal sized characters, but I think that's irrelevant, because I'm quite sure I've seen him perform it on Ryan's Ammy. It can't be due to hit stun det. because I practice it straight out of S.
The most interesting thing about it: when he performs it, the screen doesn't scroll very high before he starts the combo. He manages to land the first jH while the ground is still in clear view. I can't manage to land it that urly.