As John said, there are probably too many profiles. If you need to follow the rail curves exactly, you may need to use Sweep2 instead of Loft. The more profiles you have, the more you will get “undulations” along the length of the surface as it tries to pull the surface through each profile.
The other problem is the original “Source Profile” from which the other profiles were derived has far too many points. I estimate that it could be done smoothly, fair and accurate to within tolerance with perhaps 12-15 control points… The current curves will make for very “noisy” surfaces.
As everyone in here will tell you, the trick to getting good surfaces in Rhino is making good, clean curves. If you don’t start with those, there’s not much hope.
I don’t see any indication of the size/scale of the airfoil, but if you are going to be machining these surfaces, you need to determine the tolerance which you need to hold in machining. Then you can reconstruct your original curve with fewer points but matching the original to something like 1/10 of that tolerance. Your tools for that will be point editing with curvature graph on to make sure your edits are keeping the curve reasonably smooth. Keep a copy of the original and use CurveDeviation to compare your edited curve to the original to see where the max deviation is.
Once the source profile is good, re-do the orientation to create the other profiles from the new one. You should then get a clean, accurate loft. I do not think there is an automatic way to rebuild all your existing profiles and be assured that all are within tolerance, that’s why I suggest going back to the beginning and starting over (unfortunately).