We've reviewed a number of auto chargers for dockable iPods, but if you do much flying, what you'll likely find just as useful is an airline power adapter. Monster's iAirPlay provides both: a plug to connect to the special power plugs provided on many newer airplanes, and an accessory jack ("cigarette lighter") adapter that fits over the airline plug for use in the car. (Note that some airplanes actually have standard car accessory jacks rather than the newer airline power plugs, so you'll want to bring the car adapter when flying, just in case.)
The iAirPlay connects to the dock connector port on your iPod via a 1-meter (3.3-foot) cable, providing power for both playback and charging; when used with a car jack, a light on the car adapter indicates power. Both the dock connector and airline power plugs lock in place, requiring you to release spring-loaded clips to unplug them.
The iAirPlay worked as promised in my testing. Given its small size and light weight, it's a no-brainer accessory for frequent travelers.--Dan Frakes
Auto/airline power adapter for dockable iPods.