I suppose it has been covered before, but can't find it ...
"Flying figures cannot end their movement in a space containing another figure or an obstacle that blocks movement."
What happens if a figure is forced to stop moving in a space containing another figure or an obstacle ?
For example, a flying hero might want to open a door while staying on a space cpontaining another figure, and be caught in Paralyzing Gas.
Or a Rzorwing might be hit by a web-producing weapon as it flies over another creature (or a stone block).
Q: Can a hero with Acrobat activate glyphs or take treasures (gold, runekeys) from under a figure that is occupying the same space as the item? Can a hero with Acrobat open a door in which both spaces in front of the door are occupied by figures as long as he does not end
his turn in one of those spaces?
A: Yes to all. If this causes a hero to become paralyzed or otherwise stopped in the space due to a trap, the overlord moves the hero to the nearest empty space of the overlord's choice. Note that this is a general way of resolving situations in which a figure would end its turn on the space of another figure (the player causing that situation gets to choose the space the figure is moved to).
Or a flying hero might open a chest while a creature sits on it (legit, right ?),
No. Chests explicitly cannot be opened while another fgure is on them, according the the chest rules.