Airbus Group is already using 3-D printing for producing parts for test flights and for parts that will soon fly on commercial aircrafts. As you are reading this, a titanium alloy bracket which was printed is flying aboard the Atlantic bird 7 telecoms satellite.
ALM, Additive Layer Manufacturing as referred to by Airbus Group, is definitely beginning to shape the future of aircraft manufacturing.
Another advantage is the fact that on average only 5% of waste material is produced from ALM. Such a figure could never be achieved with a more classical method of manufacturing. NASA just sent Gecko Grippers, a 3-D printer, to its International Space Station so that astronauts can build tools notably to attach sensors and other instruments onto and inside satellites. In this respect, NASA even created a «3-D Printed Habitat Challenge Design Competition» last September and is moving closer to building a completely 3-D printed rocket engine.