Can be Stunned Through Kalista Ult?

So if you're in a ult and you throw yourself forward through a stun (like 's stun), you are somehow stunned when you land passed it. Problem with that is that you're untargetable when you fly through the air and are only able to be attacked/do anything after you land. There's nothing that explains that at all, only that you stop when you hit the first enemy champ.