Though they look relatively easy and straightfoward, I find the wings to be the trickiest part of the plane to design. What makes wing design hard for me is coming up with a good and smooth teardrop shape of the wing's chord.
In the past, I used to make wings using this method:
The next steps would be to reshape the cross section of the cylinder to produce the much sought after tear drop shape.
Unfortunately, this technique relies a lot on a good eye to ensure that the chord tapers "naturally". Often times, you'll end up with something like this:
In my Heinkel P.1078B, I explored using Catmull-Clark patches for creating a smooth chord. It did its job well, but unfortunately, I had limited control on the number of wing segments. As a result, the leading edge of my Heinkel's wing is not very smooth.
Enter the Magnet tool!
Notice how much better this wing looks like compared to the one made using the cylinder+scale method?