UngeheuerLich
Legend
A Plane glide because it has wings, which a PC doesn't have. Something flying (or actually just aloft) when the flying wears off should fall, either directly vertically. There is no momentum of movement in D&D, between turns you don't retain any movement....
I understand the ''grace period'' and my gripe is not so much about the effect but when it takes place. That ''grace period"" should be within the potions effect, not after it wears off. To be clear, when the potion's efect wears off, you are under no magic effect anymore....hence the illogicalness...
Except that the magic just has a 1 minute feather fall effect programmed into it, because having a fly spell that stops suddenly is a bit dangerous, don´t you think? I do however concede, that a dispell magic should work on the grace period to make you fall immediately.