So, I had my old Battlestar Galactica Viper, but had lost the choking hazard/missile many moons ago. I’d played with the idea of 3d printing some, but realized as I was making the wooden one that I could just cut the profile of one out of 1/8" acrylic and it would probably work. So, I grabbed a pair of calipers and measured some of the slots on the toy and guessed at some of the internal measurements, then looked at some pictures of the original ones on the web and roughed one out in Illustrator. My first attempt was a bit too short to reach back to the locking mechanism, but gave me hope in the rest of the fit so I stretched it out a bit longer and the second try seems to work

Now my kids have every chance to choke themselves or get something stuck in their ear as I did growing up