This is a video of a 450MPH R/C jet airplane. It weighs 17 pounds (almost entirely engine) and has to be launched with a long elastic slingshot. It takes some serious eagle eyes to be able to fly too, because that thing goes FAST. Like four seconds and you can't even see it anymore. Also, at what point does an R/C plane stop being a hobby and start being a weapon? Because I'm pretty sure that's what this is.
Keep going for the video, but skip to 2:20 if you just want to see the thing flying around making jet sounds.
Thanks again to Luc, who's developing a system of quadrocopters that can do skywriting without a plane, and I'm stealing the idea and getting rich.