Depending on where you live - you could do paragliding.
During my last vacation - I met a guy who learnt paragliding. And then gave rides to others for a fee.
He found a beach that was close to a small hill kinda thing. When he wanted to work - all he did is paraglided from the hill to the beach. Everyone on the beach would see him and then approach him on his landing. And he would then take 3-4 of them to paraglide one-by-one.
Did very very well.
Obviously - you can learn it for your own self - as a hobby too. No need to take others on a ride if you don't want to.
http://en.wikipedia.org/wiki/Paragliding