What is in this image? Describe it as if you were explaining it to someone from the 15th century.

Imagine a large, whimsical bladder or sac, akin to the bladder of a fish but much greater in size, soaring gracefully through the heavens. This bladder is tethered to a basket crafted of wickerwork or ropes, resembling the baskets used for carrying goods to market, but suspended in the sky. Inside this floating basket, brave souls can journey across the skies, observing the world from a heavenly vantage as if they were birds. In this particular vision, even the sky itself seems playful, with clouds that carry the spirits of the air, and one cheeky cloud is gusting a breath of wind, propelling the airborne marvel even faster through the skies. The fields below, viewed from such great heights, would appear as mere patches upon a vast, Earthly quilt.This image is not only a depiction of human ingenuity in mastering the skies but also infused with a fantastical charm where natural elements communicate and rejoice in their existence. It captures a dreamlike vision that might stir both wonder and bewilderment in a 15th-century mind.