There is no explanation for the flying fortresses written into the lore, either. I suppose there could have been a spell effect added when falling more than a certain distance, or a description given in Farglow of getting the ability to automatically slow a fall when getting the dragon memories, or something.
There was an active Telekinesis spell in Divine Divinity, but it only allowed you to pick things up or interact with objects from a distance. An active spell which allowed more general manipulation of objects would fit into the game world, but I'm not sure it would be practical in the game engine used in DKS. Once you add such a spell, then much of the world (within some weight and size limits) would need to be movable and destructible, or it would feel partly done (if you can slow your fall in full armour, then many chests should be movable, you should be able to push NPCs back or pull them towards you, possibly break doors, etc). If telekinesis was going to be a core gameplay element it would be worth the effort to implement, but possibly not if it would only be one of a bunch of spells that a player had the option of using.