Stay with a car, he can learn the basics of RC on his own with it. One thing in particular is reversed controls when the car/drone is coming toward you. Also, while drones usually have full flight stability systems most planes don't.
My stepsons first car was a grasshopper. There are a lot of parts but good instructions. Sadly, he had no mechanical ability - and still doesn't 35 years later. The good thing about that is I got to build it