If under a certain size, the rules are basically "as long as it isn't hazardous" which is vague but more or less requires common sense.
It's also not that hard to comply with RC aircraft regulations.
Plus, drones are everywhere, it's not exactly a dead hobby. Most of the people who were interested in other kinds of RC aircraft are more attracted to the much easier to handle quadcopter types.
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https://www.apogeerockets.com/Peak-of-Flight/Newsletter516
If under a certain size, the rules are basically "as long as it isn't hazardous" which is vague but more or less requires common sense.
It's also not that hard to comply with RC aircraft regulations.
Plus, drones are everywhere, it's not exactly a dead hobby. Most of the people who were interested in other kinds of RC aircraft are more attracted to the much easier to handle quadcopter types.