Aspect of the Ki-Rin: The monk’s skin takes on a golden luminescence, and a silvery mane that cannot be bound grows atop his head. He gains a fly speed equal to his land speed, but he must end each turn on the ground. If the monk does not land by the end of his turn, he falls from whatever height he has attained. The ki-rin is honorable, honest, and self-sacrificing—a monk must be lawful good to take on the aspect of the ki-rin.
So, how would you adjudicate this as a DM if the monk was simultaneously the subject of a fly spell, or similar? It seems silly to think he would fall out of the sky in that case.
Note that the monk will have a fly speed higher than 60, so the relevant question is, does he get to use the fly speed equal to his land speed without falling, if he is also under the effects of a spell?