I remember ultra-lights were a big thing like 20 years ago. Do they still sell those?
I still have a home-built ultra-light and 4 hang gliders, along with a general aviation airplane. The general aviation airplane is a Piper Cherokee and still a great aircraft, but it is 52 years old and that is about average these days.
To answer your question, yes you can still buy or build an ultra-light aircraft. They are extremely fun to fly and like a hang glider or para-glider... still require no pilot's license. In this day and age that is a miracle.
Picture of a Skypup, the type of ultralight that I own... It is almost completely made out of sheets of Styrofoam brand house insulation and thin plywood covered with fabric.