He can fly back without issue. Is it because the Aeroprism can only be used on top of Baya Malay? If so, why can't Myau just fly to the top of Baya Malay?
perhaps the distance between Baya Malay to the Air Castle was shorter than Camineet to the Air Castle. I mean, you try carrying 2 heavily armed people and a robed man with a stick to the Air Castle.
That, and I cannot imagine the Laerma Nuts lasting that long.
Laerma nuts seem to be permanent as Myau is in PS4 and is still very large. Oddly he doesn't get a strength boost or even an increase in HP after the transformation.