Character Analysis
You might try telling Buzz Lightyear he's a cool toy, but he won't believe you. This little guy made of plastic and sound chips and glowing LED's thinks he the real Buzz Lightyear.
And, though he may not save the galaxy, he ends up doing something almost as heroic.
Buzz Lightyear of Star Command
Buzz's big crash-landing might totally change the dynamics in Andy's room, but Buzz is pretty much oblivious to all of this. Buzz doesn't realize he's a toy—he wakes up in Andy's room with no memory of being made in Taiwan or shipped to a toy store in the tri-county area. He meets all of Andy's toys and starts spouting a bunch of grandiose ideas about saving the universe:
BUZZ: Right now, poised at the edge of the galaxy, Emperor Zurg has been secretly building a weapon with the destructive capacity to annihilate an entire planet. I alone have information that reveals this weapon's only weakness. And you, my friend, are responsible for delaying my rendezvous with Star Command.
WOODY: You. Are. A. Toy! You aren't the real Buzz Lightyear; you're an action figure! You are a child's plaything!
BUZZ: You are a sad strange little man and you have my pity.
Clearly, being a space ranger is a huge deal. Buzz is an important guy. He's a hero who saves galaxies. The idea of being a lowly toy with no heroic impulse (or the power of flight) seems preposterous to him. Buzz has got confidence and charisma oozing out of his pores. And the other toys in Andy's room love him for it. (Well, Woody not so much.)
We're going to go on record saying Buzz kind of likes the attention. He's a big deal, and he likes other people and toys to know it. The other toys rally around him and he's easily accepted into their society.
But, weirdly enough, Buzz doesn't care about being part of their group or playing with Andy. He's just trying to get back to Star Command. That makes Woody hate him all the more.
But, this weird delusion can't last, can it?
Babes In Toyland
Buzz's big moment comes when he sees a commercial for himself on TV… and his entire world falls apart. He finally figures out the truth. He's not a space ranger. He's not heroic or important. He can't even fly. Or save the universe.
He's just a toy.
BUZZ: I can't help. I can't help anyone.
WOODY: Why, sure you can, Buzz. You can get me out of here and then I'll get that rocket off you, and we'll make a break for Andy's house.
BUZZ: Andy's house. Sid's house. What's the difference?
WOODY: Oh, Buzz, you've had a big fall. You must not be thinking clearly.
BUZZ: No, Woody, for the first time I am thinking clearly. You were right all along. I'm not a space ranger. I'm just a toy. A stupid little insignificant toy.
This is a really low point for Buzz. This newfound knowledge has really sent him spiraling into a pretty heavy existential depression. If he's a toy, then he doesn't have any value. What does it matter what happens to him? Or who owns him? Or if he gets blown up?
If he's not a heroic, charming, confident space ranger, then what difference can he make?
Lesson Time
But, with a little help from Woody, Buzz realizes that being a toy isn't really that terrible. Buzz can still make a difference—he can make a difference to Andy. After all, if Andy loves him and wants to play with him, then he's fulfilling his destiny as a toy, right? He's making a kid happy. That's actually a pretty special thing:
WOODY: Buzz! What are you doing? I thought you were—
BUZZ: Come on, Sheriff. There's a kid over in that house who needs us. Now let's get you out of this thing.
When Buzz decides to rescue Woody and escape from Sid's room, he's made a choice. If he can't be a space ranger, then he's gonna be the best darn toy he can. He's not insignificant. He's someone. And he's someone who means something to Andy and his friend, Woody.
Oh, man, we love a happy ending.
You'll actually see journeys like Buzz's in other Pixar movies. The idea that you can't be just anything you want to be is a pretty common theme in their films. They'll create a character that has grand ideas and aspirations and gradually have him realize that he's not as great as he thought he was.
Just check out Buddy in The Incredibles. Or Lighting McQueen in Cars, Charles Muntz in Up, Mike Wazowski in Monsters University, and Joy in Inside Out.
Pixar: telling kids they probably won't achieve their wildest dreams since 1995.
Buzz Finds His Voice
Tim Allen famously voiced Buzz Lightyear, but the folks over at Pixar originally wanted Jim Carrey to do it. Of course, they also didn't have the budget to hire a major star like Carrey, so they had to move onto other options. The role was also offered to Billy Crystal who passed on it and then called that move, "the biggest mistake of [his] career." (Source)
Luckily, there were no hard feelings and Crystal ended up providing the voice for Mike Wazowski in Monsters Inc.
Buzz Lightyear's Timeline