Those airplane power adapters you can buy for your gadgets are useless without an actual power outlet for your seat–and unless you’re in first or business class, you probably won’t get one. Enter Inflight Power and its clever new adapter, which lets you draw juice from the headphone jack on your armrest.

Simply plug the cord into your seat’s audio jack, turn the dial to an in-flight channel with consistently loud sound (rock music works nicely, according to Inflight Power), crank the volume, and plug in your MP3 player or handheld (adapters are available for iPods, BlackBerrys, Motorola phones, or most any pocket device with a mini USB port for charging). It doesn’t look like the Inflight Power adapters will work for laptops, though.