Current version: 1.1.2 for Minecraft 1.12.2

Flight can be exited in a spot where the player doesn't actually have room to stand.

Further more, this lack of space validation seems to cause the player bounding box to not update correctly too. Exiting flight below this block retained the flight bounding box.

Emerging from the blockspace restores the bounding box correctly.

To be honest I think this glitch should be kept since this could be kinda useful in certain circumstances.