[mikeash]

It may be legal to fly an ultralight with no formal training, but I would strongly recommend against it. Attempting that is an excellent way to get yourself killed.

The barrier to entry for aviation is not steep at all if you approach it with the attitude that flying with an instructor is still enjoyable flying. People often think that you need to drop a few thousand bucks on training before you can fly. But not so! You'll be flying right from the start. You'll be doing it with an instructor, but if you pick an instructor whose company you enjoy, that can be a bonus, not a drawback.