Although the cockpit is essentially done, you need to add edges and adjust their position so the cockpit still looks good when you smooth the model.
Set up the lesson:
Use smoothing to preview the model and help you refine the geometry:

Edit panel, turn on
Use NURMS panel, increase the number of iterations to the usual value (for the P-47) of 2. The model is smoothed nicely, and the cockpit is smoothed all the way around. This is easiest to see in the Top viewport.

However, the blueprint image shows that the leading edge of the cockpit should be straight. You can fix this by adding some edges (as you saw when you refined the air-intake portion of the engine cowl, placing edges close together reduces the effect of NURMS smoothing).
Edit panel, turn on 
+click to select the two edges on top of the fuselage, in the new loop you just created. 
Edit panel, activate 

+click to select the two small edges along the rim of the cockpit, in the new loop you just created. To select both edges, you have to
orbit the Perspective view.


Edit panel, activate
+Z several times to undo Perspective view changes, and return to an overhead view of the P-47. 
Edit panel, turn on The leading edge of the cockpit is now straight, as it is in the blueprint images.
