There are two very good reasons to add one more item to your carry-on luggage, and the good news is that it folds up nice and small. The EZ Sleep Travel Pillow expands to become an effective divider between you and your neighbor, doubling as a soft, cushioned surface on which you can lean.
The large rectangular pad can be easily inflated once you board the your aircraft. A fabric loop on the bottom can be slipped over either armrest as an anchor; the opposite long edge can be wedged between your backrest and the adjacent seat for added vertical security. This setup allows you to shift your weight against the EZ Sleep Travel Pillow without the risk of keeling over onto the next passenger.