Now let's go on with the knee: this time we will model it with NURBS.
we'll draw the profile using Create > CV Curve Tool,
and set the linear degree to 1 in the option Box to create straight lines.



We select the curve and with the Surfaces > Revolve instrument we create one revolution surface. Pay attention to the correct revolution axis if you want to obtain the surface you're looking for. In our case it's the X axis.
We just have to position the knee correctly according to the project sketch we are referring.



Using the same polygon tools we create the thigh.



For the second joint (our sketch actually requires 2 knees or joints...) we simply copy that one previously created...



Duplicate it, move on and scale it a little....
This will be the principal joint for cockpit support.



Now let's model with the polygons tool the joint cover in the frontal view.




And Extrude it. Same procedure for the final part of our leg, as shown in the picture below...



And same procedure also for the cabin. First the profile in side view...



..then the extrusion in perspective view..




Now we select the frontal part of the cabin, we scale it, extrude it an move it inwards, so we obtain the cockpit glass.....