Small soft marsupials that often are found quietly snoozing since they are nocturnal. When they awake they can sound as loud as a hand drill if they are startled. They are not found wild in the US, only kept as companions. 

Are they the same as a Flying Squirrel?

No, they are completely different and are not even related! Sugar gliders are marsupials and flyers are rodents. Sugar Gliders have a musky smell and scent glands and flyers do not. Gliders breed all year round and will breed very well and easily in captivity, Flyers breed once a year and are not very successful when paired and bred in most captive situations. They have different diets, fur color fur texture, smell, and noises. The only things they share is that the both glide, they are the same size and they both form deep bonds with their owners.