Hypo #4

Gary Guenther and Jackie Yanover buy a Robinson R66 helicopter as "joint tenants with right of survivorship" while they both live in Illinois

Guenther, having graduated from law school, passed the bar, and earned his pilot's license, decides to open up a law practice in Alaska, specializing in springing-executory-interest litigation

He flies the R66 to Juneau, contracts with a fixed base operator there for hangaring and maintainance, and uses it to travel to see potential clients

He also makes it available to a local flying school to give flying lessons in it, at $50 per hour (the market rate for R66 time is $600 per hour).

Yanover sues him for conversion of the aircraft and the flying-school rental proceeds.