Stunt Island is a plane sim based around the concept of being a stunt pilot in the movie industry. You get specific instructions on how to fly what and where, and you need to pull it off.
My favorite mission was to fly a duck, drop an egg on the police car. Another one was landing a cessna on a street and pulling up to a burger joint.
Or if you didn’t feel like completing these contracts, you could just grab whatever you wanted, and explore the island.