Catman
You are confusing Flying Squirrels with Squirrel Gliders
They are two seperate speciess.
Squirrel Gliders are Gliders and are related to Sugar Gliders
Flying Squirrels are a part of the Rodent family, they are not remotely related to Gliders.
Squirrel Glider grow to about 300grams, have a pointier face and narrower ears than Sugar Gliders. There diet is very similar to Sugar Gliders except that they eat more insects. Squirrel Gliders also make different noises than the Sugar Glider.
Both Sugar and Squirrel Gliders may live within the same habitats but to do not intergrate with each other, however in captivity they can and will interbreed.