Hi Terry, The difference is one of construction and the types of wood used.(Flamenco generally Cypress and Spruce and Classical, Rosewood,Spruce & Cedar) Of course this also has an efect on the weight of the guitar with Flamenco due to construction is much lighter than a Classical guitar and much thinner in the body. The "Action" of the flemenco is much lower than the Classical. These factors and a few more construction differences is why the Flamenco and Clasical guitar sound is so different.
There are other factors but rather than labor the answer this is the "Basic" difference. However, should you want the "Full Monty" answer we can oblige.
Fenderphil.
more posts...