Early on in The Theory of Flight, we hear the sounds of a couple having strenuous sex. The camera deliberately pans across a room to find a young woman in a wheelchair watching two enthusiastic lovers going at it on her computer screen. Sex is at the heart of the film, but this is no ordinary love. The film charts the path of two struggling individuals who challenge the limits of their handicaps and find liberation.

Physically handicapped Jane (Helena Bonham Carter) has progressive Motor Neuron Disease (otherwise known as Lou Gehrig's Disease, or ALS), and is starting to lose her ability to make coherent speech. Richard (Kenneth Branagh) is, arguably, mentally handicapped; he's a struggling artist and a general ne'er-do-well who likes to build homemade flying machines. After he crashes one of these contraptions off a London building, he's sentenced to 120 hours of community service and is assigned to be Jane's caretaker, which turns into something more than a trip to the park now and then. Jane's a feisty free spirit of 25 with a quick mind and a biting tongue (the f-word is the cornerstone of her vocabulary). Beyond her terminal disease, Jane has a bit of a problem. She's a virgin, and she wants Richard to help her realize the passage to adulthood before it's too late, noting that 'sex is even more important than money. Money is the means to an end-sex is the end.' Although a real relationship is obviously impossible for her, Jane believes 'that doesn't mean I shouldn't get as much as I can,' and in exchange for his services, she helps the able-bodied Richard find direction in his aimless life.

Carter delivers an ultimately quite moving performance and has mastered Jane's vocal inflections, though with her clenched jaw and slurred speech, you have to strain a bit to make out some of her dialogue. Jane sometimes reluctantly uses a speech machine to deliver long, erudite passages of dialogue, full of wit and feeling. When Richard declines to sleep with her, she cracks, 'Apparently, there's no such thing as male sexual altruism. Half the women of the world commit it every night.' Carter's real-life paramour Branagh never earns anywhere near the same level of sympathy, and his character remains something of a cad as he noodles around his barn, building a plane which eventually allows him and Jane to literally take flight. It's impossible not to groan when Jane asks Richard if the reason he won't sleep with her is because she's a cripple and he answers, 'No, it's because I'm a cripple.' Well, hardly. A little emotionally immature and wayward, perhaps, but so are a lot of guys.

The Theory of Flight's final 10 minutes or so are lovely and touching, but the film sputters a lot along the way. Director Paul Greengrass resorts to some cutesy, briskly edited scenes set to the likes of Van Morrison to show how the pair bond, and there's a lot of nonsense about Richard planning to rob a bank so that he can hire a male prostitute to sleep with Jane, since he won't do the job himself (though there's a funny bit when Jane says she wants something special, like Richard Gere. Richard assumes she's referring to Pretty Woman and reminds her the prostitute in that film was the woman, but, in fact, she means American Gigolo). Carter's bravura performance is the reason to see The Theory of Flight, but it's a shame that nothing else in the film matches the obvious care she put into her role.

--Chris Grunden