X-Plane has gone universal. It should run very well on the new Intel macs. People ran it on the G4 Mac mini's so the MacBook should scream on it.
Go to their website x-plane.com and get the update/demo. According to the website you should be able to get 85 FPS.
Oh, and open GL is a very Mac thing. It has been the main graphics driver on Macs since long before OS X.