I fly RC airplanes and Parma makes some various scents to add to Nitro fuel. I have never used it in any of my gasoline powered planes, but I don't knnow why a little couldn't be used in gas as well as alcohol. Here is a link to Tower Hobbies that sell the scented fuel oils if you want to check them out. Scroll down the page to Parma.
TowerHobbies.com | Search Results