Since I don't know the details of the 'barn full of cars story', it's hard to say who the main characters are. But it could be the owner of the barn, or the person who discovers the barn full of cars.
In the 'barn full of cars story', there might be the collector who amassed all the cars in the barn as a main character. There could also be a local mechanic who becomes involved if the cars need fixing. Another possible main character could be a young adventurer who stumbles upon the barn while exploring the area.
The 'barn full of cars story' might be related to a collection of cars stored in a barn. Maybe it's a story of a person who had a passion for cars and over time filled a barn with all kinds of automobiles. It could also involve the discovery of the barn by someone else, like a collector looking for rare cars and stumbling upon this hidden treasure trove of vehicles.
I don't know for sure as the story isn't widely known to me. But it could have a hat - maker as a character, who fills the barn with hats.
In the 'barn burning story', the father is a central character. He is a symbol of the frustrated poor. His actions of barn burning are a reaction to the inequality he feels. The son is another main character. He witnesses his father's actions and is constantly in a state of internal conflict. He is influenced by his father's actions but also has his own sense of morality which makes him question what his father does. This internal conflict within the son is a major part of the story.
As I haven't read it, the main characters are probably the birds. There might be a lead bird among them.
Perhaps the main characters are the entrepreneurs who are investing in flying car projects. They play a crucial role in pushing the idea forward. Also, there might be some test pilots who are involved in the early flights of the prototypes.
I don't know the exact main characters as I haven't read it. But it could be the owner of the barn, perhaps an old farmer who has a deep connection to the place.
There could be farmers, as it's a barn which is usually associated with farming. And of course, there might be animals like cows, horses, chickens etc.
In the Cars 3 story, Lightning McQueen is central. He's the racer we've known from previous movies, now facing new challenges. Cruz Ramirez plays a major role as she helps McQueen train and also discovers her own racing abilities. Sterling is also important as he owns the high - tech training center. His ideas about racing and how to manage racers add to the story's conflict and development.
Since it's a true story about riding in cars with boys, the main characters would probably be the narrator, who is most likely a female, and the various boys she has these car - riding experiences with. These boys could be friends, love interests, or just acquaintances. They each would bring their own personalities and stories to the interactions that happen during the car rides.
There could be a farmer as a main character. He takes care of the animals in the big red barn.