The composite construction makes a big difference in making
possible the use of supercritical airfoils. These airfoils need a
slick surface, so much so that flying in rain degrades their
performance to the point that they can become dangerous. You'd never
build a wing like that using sheet metal and rivets. Just the lap
joints or any waviness in the aluminum would cause trouble.
Composite looks nice, but I became allergic to some of that
stuff way back in the '70s. And in the cold winters here I've seen it
crack and delaminate. My preference is for something more resistant to
everyday life. Kinda like my old truck.

Dan