How does it stay aloft?

The flying squirrel is incapable of actually flying, but by extending their arms and legs they can control their fall by gliding. The webbed part of the flying squirrel is similar to hang gliders and both the hang glider and the flying squirrel use certain areas of the thing or the animal to allow them to control their fall.

What is the Internal and External structure of a flying squirrel?

Internal Structure:

External Structure:

The external structure of a flying squirrel allows it to control its fall and slow down to land on other branches or the ground. Their external structure means that when they land all the have to do is rotate themselves so that it slows down their movement.