This is a flying propeller launcher toy, which uses a squeeze mechanism instead of a pull cord.
Just attach the propeller disk to the launcher, find an optimal way to hold things, aim, then quickly squeeze to send the propeller flying! Careful not to pinch your fingers!
It can be a little tricky to use, so it may not be ideal for younger kids.
The launcher does not require any assembly, and prints in place, ready to use. But I do recommend using tree supports, since there's still a bit of an overhanging area to deal with. They shouldn't be too hard to remove tho.
Also, I advise changing the wall print order to outside-in, aka outer-wall-first mode. This helps ensure the internal hinge and gears don't fuse together. If you use Cura, you can also try setting the Slicing Tolerance to "Exclusive" mode, tho I've printed one on "Middle" and still got it working.
I tried to make the gaps around the gears and joints wide enough that it should usually print fine, without locking up.. But it'll always be a bit stuck at first, usually around the small gear. So depending on filament and how good the printer is, it may require a little working it, to get that part moving freely. I typically have to squeeze it a bunch of times rapidly, to loosen things up, after printing.
Important: Before printing the Disks, you may want to consider printing a "Disk Remover Tool" to help you get the disks off the print-bed. Sometimes the disks are kinda fragile and the core part sticks to the bed a lot better than the rims, so it can be tricky to remove without the tool.
As for the Propeller Disk, try to choose settings that will keep the disk as lightweight as possible. I use 2 walls, low infill, only 2 top/bottom layers. I haven't needed to use support for the propellers, so I don't suggest it.

Want more POWER? Check out my new 64x gearbox-based Disk Launcher!
https://www.thingiverse.com/thing:6412255