Last fall, GE Aviation quietly purchased two small 3-D–printing companies, Morris Technology and Rapid Quality Manufacturing, and in doing so made a loud statement: 3-D printing will shape the future of aircraft.

For the past decade, aerospace manufacturers have used additive printing to prototype select parts. The process is fast and affordable. “We can make the first batch of parts faster than any toolmaker can make the molds and jigs,” says Brett Lyons, a materials and process engineer at Boeing Research & Technology. But companies used only a few materials and printing techniques, such as Selective Laser Sintering (SLS), a process that uses lasers to bond thin layers of metals or thermoplastics.