When i was young I made some model planes with balsa wood frame and covered in tissue, Keil Kraft was the popular make. I wonder how things like balsa cement ,and particularly dope used to finish the tissue covering , are viewed nowadays for use by children. Dope was a particularly potent smell !
I built a lot of stick and tissue balsa models before high school. One of my favorites was a free flight towline glider by Sig
https://outerzone.co.uk/images/_thumbs/plans/3869.jpgAlso built kits from Scientific, Guillows, Carl Goldberg, some others I can't recall.
The model club I was in, in Cleveland, OH, had three or four members who were NASA guys and designed their own airplanes, and would give out the plans, so I built a couple of those too. The club was mostly into free flight, but also control line, and we would have lively control line combat contests, where each plane tows a streamer. Cuts on the other guy's, and time aloft, made points. The 1/2A class, using COX .049 engines was something a boy with a paper route could afford to compete in. They were generally all simple flying wings and usually died young.
https://youtu.be/e7VdjENmKlU?t=583I think that exposure of the chemicals to kids is kind of a non-issue, because kids have no interest in the activity. All the hobby shops I know of closed a couple decades ago. I think most of the mechanical hobbies have been replaced by virtual world, or computer adjacent hobbies. Making things with 3D printers, which requires virtual model building at the most advanced level is a popular "boy engineer" activity, but I suspect that gaming absorbed a lot of the model building types.