Although they've been around for ages, for some reason paper airplanes have never been adopted for commercial use. It could be because they get soggy when wet, they lack any kind of flight controls, or because you would need an incredibly huge piece of paper in order to make one big enough to carry a human passenger. In any case, practical paper airplanes have now perhaps come a baby step closer to reality, with Tailor Toys' Power Up electric power module for paper airplanes - it allows you to mount an electric propeller on your paper airplanes, so they can fly under their own power.
The kit consists of a capacitor that clips onto the plane's nose, which is connected to a rear-mounted propeller via a carbon fiber shaft. The capacitor takes a 20 second-long charge from a separate battery pack, which contains three AA batteries. One charge provides enough power for 90 seconds of flight. That's probably plenty of time, considering that users presumably have to chase after their powered paper planes in order to get them back.
That being said, a neat add-on for future versions of this product might be remote-control ailerons, so the plane's flight could actually be controlled. Of course, once it got that complex, it would probably be simpler just to buy a complete RC model plane.
Although you can add the module to whatever design of paper aircraft you like, the Tailor Toys website does feature instructions on making planes that should work particularly well with the kit. The Power Up module is currently available on Amazon, starting at US$17.49.
The video below shows what kind of flight is possible with the device.