At times, How to Train Your Dragon is like a Harry Potter film with less clutter. It has winningly Potteresque teen-dragon-slayer classes, a queen-bee dragon as grand as Godzilla, and a layer of age-of-terror allegory about the ignorance bred by jingoism. The Night Fury, named Toothless, is a voracious yet inwardly serene beastie whose trust must be won, which Hiccup does by feeding him slimy fish, building him an artificial tail, and saddling him up. How to Train Your Dragon rouses you in conventional ways, but it’s also the rare animated film that uses 3-D for its breathtaking spatial and emotional possibilities. When Hiccup and Toothless take to the sky, we’re free of constraint, aware of the space on all sides. At moments like those, the movie makes you feel in every way miles high.