“I am more than just a cropduster!” Dusty Crophopper proclaims at the beginning of “Planes,” and it’s hard not to sigh. In recent years we’ve seen a penguin that wants to dance, a video game villain who wants to be a good guy and, most recently, a snail that wants to be a race car. The children of the world get it. You can be whatever you want if you work really hard and have charming sidekicks. But after a trying first act, this DisneyToon Studios release finds a nice cruising altitude, embarking on a world tour that yields some pleasant surprises. “Planes” was supposed to debut direct to video, before Disney decided it was deserving of the big screen. (Story idea: A video store cassette that dreams of being a theatrical release!) “Pla...