Buy a USB charger, a battery holder, 4 or 8 eneloop batteries, a USB to car adapter and a small universal battery charger. I just bought two packages, from CellPhoneShop - basically a cheap chinese redistributor.
I'd recommend DealExtreme, but basically get a small battery or crank kit and an adapter to go from a cigarette lighter to usb, thence from usb to your nokia charging port (not your usb port!!). The chargers come with multiple tips for various devices.
The small battery/crank kit would do well on the plane. The cigarette lighter to usb will do well wherever you can find a cigarette lighter and the plain usb wherever you can find a usb port,
WARNING - make sure tips and power are compatible (polarity etc.).
But now in a small space (with 4 eneloop AAA batteries) I've flexible charging solutions for both my Razr and my 810.
WARNING II - charging over usb is significantly slower! I let my 810 get down to "less than 1 hour left" and it's been charging (screen on, occasional usage) for 5 hours and only says it's good for 5 hours.
/edit - cost was $17 for all but batteries & charger, plus shipping.