I don´t make a boolean there. The Wing is an another Object and i don´t plan to Combine it with another Object. When i Combine all the little extra Objects with the Main Object i become Problems with the UV-ing later. It´s easier to have more simple Objects then one big Object with a complex mesh.

And I need the Edge to sharpen the intake on the Top. Think the next screen will speak for itself. The marked Edge is the Edge you mean.