There are 600,000 GA pilots in the US. It’s ignorant if you think we all have Gulfstreams.
My dad was a pilot and engineer, and we built many things together in my childhood (go-carts, computer video games, an automotive speedometer, more).
But there was one thing that I always wanted to do with him: build an airplane. As a 13 year old, I found different plans from vendors, created a budget, put together a basic timeline, but could never convince him to do it.
In fairness, building a plane is a huge multi-year commitment, and almost certainly more expensive than buying a used Cessna. But the price is not completely out of reach for many folks (<$100k). The real draw is the amount you learn during the process and seeing your handiwork.
I'm still sad we never did it, but it was a big ask of a dad with a full-time job from a twerp son. As a consolation however, he did buy a small wing-section kit and we got to rivet a few panels together over a weekend. First time I ever used rivet fasteners!