If I'm traveling for work (i.e. not a vacation), being able to do billable work while in the air means I'm not losing tons of $ in addition to suffering through

If I'm traveling for work (i.e. not a vacation), being able to do billable work while in the air means I'm not losing tons of $ in addition to suffering through a coach flight. Obviously there's some work that can be done off-line, but having net access would improve my ability to do billable work while in transit. If you're going on vacation, don't bring your laptop:)