UV Exposure on Flights: What Every Passenger Should Know
Commercial pilots have roughly twice the melanoma incidence of the general population. Researchers attribute much of this to UV radiation at cruising altitude — the same radiation that window seat passengers absorb on every daytime flight.
UVA vs UVB: what airplane glass blocks
Most commercial aircraft windows are made of acrylic (Plexiglas), which is an effective barrier against UVB rays — the short-wave radiation responsible for sunburn. UVB is almost entirely blocked by the window material.
UVA, however, is a different story. Airplane acrylic transmits approximately 40–55% of UVA radiation. UVA penetrates deeper into the dermis than UVB, contributing to collagen breakdown, premature aging, and — critically — melanoma. Unlike UVB, UVA produces no immediate sunburn sensation, so passengers rarely notice they're being exposed.
Why altitude makes it worse
UV intensity increases approximately 10% per 1,000 meters of altitude. At typical cruising altitude of 35,000 feet (~10,700 meters), UV is roughly 2–3× more intense than at sea level. The thinner atmosphere at altitude absorbs and scatters less radiation before it reaches you.
The effect is amplified near the poles in summer, when the sun is at a high angle for extended periods during polar routing, and at high latitudes where ozone is thinner. Long-haul flights over Canada, Greenland, or Scandinavia in summer have among the highest UV exposure profiles of any commercial routes.
Window seat vs shade seat: the difference
A 4-hour daytime flight in a window seat on the sun-facing side is estimated to deliver UV equivalent to approximately 15–30 minutes of midday sun at sea level — depending on latitude, season, and flight direction. For reference, it takes as little as 15–20 minutes of unprotected midday sun exposure to cause damage to fair skin.
Choosing the shade side of the aircraft reduces this exposure dramatically — often to near zero for the majority of the flight. FlightPath identifies which side stays in shade based on the sun's position along your exact route.
SPF recommendations for flights
Dermatologists recommend a minimum SPF 30 for any window seat passenger on a daytime flight over 2 hours. For long-haul flights, high-latitude routes, or flights during summer months, SPF 50 is preferred. Apply before boarding and reapply every 2 hours for very long flights.
FlightPath's UV Dashboard calculates a personalized SPF recommendation for your specific flight — based on your route, altitude, departure time, and estimated sun exposure time on the window side.
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