"Up" is a wonderful film, with characters who are as believable as any characters can be who spend much of their time floating above the rain forests of Venezuela. They have tempers, problems and obsessions. They are cute and goofy, but they aren't cute in the treacly way of little cartoon animals. They're cute in the human way of the animation master Hayao Miyazaki. Two of the three central characters are cranky old men, which is a wonder in this youth-obsessed era. "Up" doesn't think all heroes must be young or sweet, although the third important character is a nervy kid.