If a fluffy toy can reach 400 km/h in the thin air, Brand reckons a 9kg glider can easily crash through the sound barrier.
He's designing it with Mach 1.5 - about 1800km/h - in mind.
Brand will pilot the carbon-fibre craft via remote control, watching the flight in real time via goggles linked to a camera in the craft's nose.
"I'm going to be able to steer it as if I'm in the cockpit," he said.
"An on-screen display will show my altitude, my heading, and an artificial horizon."
As the craft nears Earth, he'll pull it out of a supersonic, 15km nosedive and, hopefully, glide it safely to the ground. This will mean changing the centre of gravity, possibly by expelling some kind of liquid. He's also experimenting with wings that can change their position mid-flight, like those on advanced fighter jets.
If he pulls it off, Brand's name will pepper the aeronautical record books - from fastest glider to fastest remote-controlled plane.
The idea came to him as he discussed space travel with his father, Robert, a longtime space enthusiast who has won awards from Nasa.
"It's the test flight for a space re-entry vehicle," he says.
Why do it? "Because we can, pretty much."
The project, dubbed Thunderstruck, will take between six and nine months to get ready, at a cost of about $88,000, according to the older Brand.
The two hope to raise over $20,000 on crowdfunding site Kickstarter.
If they don't, they're adamant they'll still complete the mission - but it might take a little longer.
- AAP
