Travel much? You need one of these.

A device that draws power from the in-flight headphone system to charge most anything by USB:

The Inflight USB Power unit plugs into the passenger seat audio jack and outputs regulated power to the attached USB charging cable/connector.

Whether I can charge something via USB has figured significantly into my tech purchasing decisions over the years, and this quite justifies that approach.  I suspect that if everyone used one of these things, it wouldn’t be too kind to the in-flight entertainment system, but 1) the airlines should be running power to every seat anyway, and this should spur them to that, and 2) have you *seen* the kind of people that populate coach these days? They couldn’t read this post, nevermind order and use one of these.  It’ll be safe to use.

Via BoingBoing, via Lifehacker, etc.