The wings for the Boeing 787 Dreamliner are not built in the US. They come from Japan and they make the journey in the 747-400LCF Dreamlifter. The process for unloading them is very well practiced. The aircraft lands and is parked up. The tail is then swung open to expose the cavernous hold. A transporter pulls up behind the lane and elevates its deck to level with the aircraft. The wings are in a cradle that then slides out of the plane and on to the transporter. It then backs away and lowers down before driving the wings into a storage building.
While this was going on, other fuselage parts could be seen inside. With production running at a high rate, this process is repeated every few days. I have never yet seen the Belugas at work for Airbus doing the same sort of thing but I would like to some day. Their new aircraft are currently being assembled so they will soon have more capacity. I don’t know whether Boeing will need more of the Dreamlifters at some point but the current fleet seems to be kept busy.