Why do I get a sore throat after flying?

Airplane cabins are drier than most deserts, with humidity often around 10 to 20 percent, and your throat lining is built for something closer to 50. Hours of breathing that air dries the mucus layer that protects your throat, leaving it scratchy and raw by landing, and the NHS lists a dry, scratchy throat as a classic sore throat symptom. Talking over engine noise for hours strains things further, and if you mouth-breathed through a nap, you skipped the nose's humidifying job entirely. Post-flight sniffles get blamed on recirculated air, but the drying effect is the more reliable culprit; either way, the pattern is usually irritation, not infection, and it settles in a day or two. Prevention is hydration and protection: drink water steadily through the flight, go easy on alcohol and coffee, which add to drying, suck sweets or lozenges to keep saliva flowing (an NHS sore throat tip), and use a saline nasal spray so you can keep breathing through your nose. If the sore throat comes with fever, swollen glands, or white patches on your tonsils, or lasts past a week, treat it as a normal sore throat question and follow the NHS's when-to-get-help advice.