The Inflight Power Recharger ($35 to $50), about the size of a small tape measure, converts the audio output from an airplane's passenger seat headphone jack into power that can recharge your iPod, iPhone, RIM BlackBerry, and any other handheld devices that support USB connections.
Here's how it works: At your airplane seat, find a music channel with up-tempo tunes; turn the volume all the way up; plug your gadget into the recharger and the recharger into the airplane seat audio output jack. You don't have to be in an airline seat to use the recharger, however. With two AAA batteries the Inflight Power Recharger can juice up your device without an airplane audio jack.
I tested the Inflight Power Recharger with my video iPod on two recent cross-country flights. The device extended my iPod's playback time by about 30 minutes--but it took nearly 2 hours to get that charge. And it was awkward to have my iPod and the recharger in my lap, dangling from the airplane seat audio jack.
The iGo powerXtender ($16) is another option for gadget recharging in transit. The portable device uses two AA batteries to recharge iPods, iPhones, and other gadgets, wherever you may be. But you've got to buy a tip to connect a device to the recharger, and a tip that fits iPods and iPhones costs $13. Plus, they're relatively small and easy to lose. However, with so many available tips, it's likely there's one that fits your small gadget.