Strange Sky Creatures

In doing research for my Epic Story (hu-hummmm, do I hear laughter?), I ran across this interesting set of stories about sky people, storm wizards, and their demonships (yes, yes, there are such stories, dating back to the 9th century).

And I ran across this terrifying picture:

Can you imagine a world where our sky would be populated by creatures as monstrous as those found in the ocean?  They would prefer to sail high above terra firma, in the stratosphere and mesosphere where the air is exceedingly scarce so that if those creatures were to get too close to our own sea level, they would "drown."  However, they would occasionally be known to descend upon us and cause terror (kinda like how whales beach and no one knows why). 

You know what?  I'm really glad our skies are (currently) monster-free!