If you feel like you've taken a beating after spending eight hours on a plane, try spending a shift on the assembly line that rolls out the flying metal tubes you so hate. It takes two humans to install each of the more than 60,000 rivets that hold a Boeing 777 together: one firing the rivet gun, the other holding the steel bucking bar that forces the fastener into place. The benefits of this tiring job include repetitive stress injuries to the arms, back, and shoulders.

To improve life on the line, Boeing took a note from Kenny Chesney: no shoulders, no back, no problems. In other words, it brought in robots. Boeing installed the Fuselage Automated Upright Build system at its 777 factory in Everett, Washington, in December, 2015. It started out assembling the front section of each fuselage; this month, it takes on the rear as well.

After drilling all those holes, the robots work in pairs, mimicking the humans they replace. They save Boeing money healthcare costs and improved productivity. "If you drill a good hole, it'll drill 50,000 good holes," says Brad Zaback, who oversees the 777 program.

The benefits of this system, which took Boeing a year to develop, go beyond ache-prevention. Where Boeing used to rely on floor-mounted assembly rigs, the FAUB system is mobile, rolling around the assembly line on autonomous guided vehicles. After the human employees position fuselage panels in place, the robots roll in and rivet them together. Although the bots experienced some trouble at first, they've settled in after more than a year on the line. "They've really taken over that job," says Zaback. "They are going faster and faster."

So the next time you're at 30,000 feet, be thankful for the robo-twins who helped you get there.