When on a multiplayer server, when finding a chunk error I "floated" (for lack of a better word) through the empty air slower than water... I then moved to a cave. When the chunk loaded, and the lag was gone, I was still in the cave. I have no idea why.
TESTED ON VANILLA, BUKKIT AND TEKKIT, ALL DO THE SAME// EDIT: When "Floating" you can't go up, only down. I have fallen out of the world like this. Also, when "Floating" if you are in a block when the chunk loads up, you either 1. Go to the top most block. 2. Sir_Mr_Bman Suffocated in a wall! 3. Teleportation to Y=-100