No, not the 1976 Russ Meyer film.
I'd call it Pixar's greatest movie to date. I'm a huge fan of A Bug's Life, Toy Story, etc. but those are clearly more conventional fare. Like WALL-E and Ratatouille, Up is refreshingly uninterested in having a wisecracking young protagonist in a merchandise-friendly story. (All three were hard to sell to Disney.) Ratatouille starred a rat. WALL-E was a trash robot that couldn't talk. Up stars a grumpy old widower based on Spencer Tracy and Walter Matthau, who's obnoxious to everyone except his wife and she's dead.
Similarly, as with WALL-E, the story is formula-busting. For much of the film there isn't a villain, or even an enemy. Instead I think the plot carries itself entirely on charm. Carl Fredricksen meets a girl, gets married and lives happily with her until death do them part. That's the most beautiful part of a beautiful film. After she's gone, Fredricksen is a square-faced, square-fingered Muppet who's so reluctant to give up his home that he gets hundreds of thousands of helium balloons and sends it up into the sky. Don't ask yourself about the physics of this. You might also prefer not to wonder about how a long-lost pensioner in South America could be so well-stocked with food, fuel, ammunition and voice-creating cybernetics beyond any known science. It doesn't matter. It's a fantasy. I might have been grumbling if the film weren't brilliant, but it is, so I'm not.
The story is full of meaning and I could spend all day dissecting it, in a good way... but I'm not going to. I love its message and its heart. However there are also lots of other things to admire, which deserve attention too.
The most widely praised section is the beginning, obviously. Everything about it is a delight. I loved its 1950s (?) era so much that I was disappointed to leave it. I love Ellen and her hair. I love her hamster. "You don't talk much... I like you!"
Later on, I loved the creatures. Dug the Dog is the best dog in all movies. "My name is Dug. I have just met you and I love you." I love his dog-like tics ("squirrel!", "point!"), even if the latter's a homage to Disney's Pluto. Even had the rest of the film been garbage, it would still be worth watching for Dug. Note the jokes about dogs being colour-blind, for instance, which are quietly inserted and then never pointed out. You can simply notice them if you want to, or not. ("Grey One standing by.") They got a veterinarian and dog behaviourist to teach them how a dog thinks, instead of how people (and animated movies) more usually assume. Then there's Kevin, whom I adored for his body language. The way his head stays motionless on its long neck while his entire body rotates, for instance. He doesn't talk or think. He's not a Dreamworks feathered human played by Will Smith. He's an actual, genuine, 100%, avian-brained, large-as-life bird with a delicious superabundance of birdness.
I loved the old dude fight. If there's ever a fifth Indiana Jones movie, I want it to come out in another twenty years and to be like this. (It'll fail, just as The Incredibles stomped all over Fox's Fantastic Four movies, but that's no reason not to try.)
This is a film that can do runaway action better than anyone bar Spielberg, but also isn't interested in it and treats it almost as third-act doodling. It was the second animated film to be Oscar-nominated for Best Picture (after Beauty and the Beast) and the first to be nominated for Best Animated Feature at the same time (which it won). It has Oscar-winning music. Everything about it is simply at a higher level than in other movies, by which I don't mean helium balloons. Interestingly it also had almost no merchandise, with Pixar's regular collaborator Thinkway Toys calling its story "unusual" and "hard to promote". Of course a lack of merchandise doesn't in itself make a film better or worse, but it's refreshing simply for being so different from the normal thought processes of the Hollywood movie machine these days. (Interestingly Pixar's most merchandise-friendly franchise is Cars, which for me is also their only flop.)
Even the child actor's great. The Japanese-American child is played by a real Japanese-American nine-year-old, who's note-perfect throughout.
It's unique. I don't know of another movie remotely like it, although one could suggest influences (e.g. Conan Doyle's The Lost World). I like its combination of unusually stylised character designs and delicate, precisely observed details. It's a silly, wilfully absurd fantasy that's utterly serious about its themes and its message, while being by turns moving and hilarious. It's a thing of beauty. I'm a Pixar fan, which should follow naturally from the fact that I'm alive and breathing, but this is the first Pixar film I've gone this apeshit for since the Toy Stories and A Bug's Life.