This is just intended to be a short entry for those readers who might be interested in a couple of the items mentioned in this latest adventure story set in future life of Dan and Don.
First, there's the GAU-17 weapons system. Here's a picture shown on Wikipedia. Note that there's a very large format version of the picture that is downloadeable. Note the stream of fire emerging from the muzzle. Also, take note of that blurred portion of the image just to the left of the gun's receiver. That's the stream of spent brass being ejected by the weapon.
Here are some other pictures of the weapon type.
And here's a webpage describing the weapon system's general characteristics.
Then, there's the human flying wing.
First, here's a news article that describes this phenomena.
Then, here's the webpage maintained by the pilot. This includes video of his flights.
I hope that my recent readers have found these items to be of some interest.