I now keep Zicam Ultra with me when I travel (all year around).
I once got stuck in a middle seat (full flight) next to a woman coughing, sneezing, nose- blowing, etc. No amount of "avoidance" on my part, including leaning as far away from her as I could, not touching my face, washing my hands at the first chance I could get, etc. prevented what felt like the absolute worst cold I ever had ever "caught" in my life.