To prevent the "post-flight flu" in 2026, the most effective strategy is maintaining hydration and nasal moisture. Airplane cabins have extremely low humidity (often under 20%), which dries out the mucous membranes in your nose and throat, making it easier for germs to infect you. Drink at least 8 ounces of water for every hour you are in the air and use a saline nasal spray every few hours to keep your nasal passages moist. Additionally, use the overhead air vent to your advantage; pointing it directly down in front of your face creates a "curtain" of filtered air that can push away stagnant germs. Finally, practice strict hand hygiene—sanitize your hands before eating or touching your face, and use a disinfecting wipe to clean high-touch areas like your tray table, armrests, and the seatback entertainment screen.