I have never seen anything mentioned anywhere about what I am going to share with you, and is probably the most important step you can do in finishing your newly created masterpiece. What smoothing out the lines really means is that you don't want some of the lines on your plane to be sharp or creased very well. What you want is nicely rounded lines. Just by smoothing out some of the lines on your plane can make the difference in your plane flying, or dramatically whirling itself into the ground.

I have tried to make this part as easy as possible for you, and I hope I have succeeded. 

Starting with the jline original above, you will notice that I have added some blue lines along the wing folds to indicate were you will smooth the lines. Along these lines you will need to smooth out the wing line with your fingers. Just place your index finger on the bottom side of the wing and your thumb on the top side of the wing, press together and drag them to the end of the wing. Do this several times for both wings. Simply by doing this dramatically improves the planes ability to fly.

That is all that is needed for the jline original. Below you will find the rest of the planes with similar blue lines. These lines will indicate as they did for the original, were you will have to smooth the lines. Also pay attention to the length of the line, this to is important.