As Brandon said, depending on the shape you want it might be done with a variable radius blend. You might use a Sweep. You might use a Loft or Boundary Surface. You might even be able to do it with a Fill Surface. There are lots of ways to skin that particular cat and which one works best is not easy to say up front.
Can you post some example SolidWorks files of what you are trying to achieve. Being familiar with aircraft design I think I know what you are looking for, but would like to see what you are trying to work with to know for sure.
Then all of us on the forum can weight in with possible solutions.