As I understand it our aircraft are attacking Al Queda/ISIS both of which are Assad's enemies, so why would his aircraft be a problem for us? They would be attacking the people we are attacking.
Turkey doesn't much like Assad, it doesn't like ISIS, it however mostly doesn't like the Kurds. The Kurds don't like ISIS. So exactly what Turkey would hope to achieve by a no-fly zone escapes me.
However if the Russians supply pilots and ground crew, those Foxhounds become something very interesting.
ISIS however isn't a normal army it is very dispersed and difficult to defeat from the air. Ultimately ground troops have to be there. If they are going to be defeated, like it or not, we should work with Assad.