Just a reminder that your mileage my vary, but: Business Week makes the case for why business travelers shouldn't work on planes:
I'm sure this can all be true, but I do some of my best work on planes. Long work-related flights are restorative: it's a quiet space between days of hustling to get ready for a trip and a couple days of talks or workshops or consulting, a span of ten or twelve hours where I can do nothing but sit and think. Approached in the right spirit, it's a great place to be reflective and creative, despite the cramped seats and physical disorientation.