Duh. Planes are arid environments that challenge even the dewiest of complexions. When plenty of water, sleep and the legendary skin saver Elizabeth Arden Eight Hour Cream Skin Protectant (HK$176.50; www.strawberrynet.com) are not enough, try a face mask. I'm serious. Not all of them make you look like Jason from Friday the 13th. There are plenty of cream-form skin masks (and there have been for ages) that are barely visible. Laneige's Water Sleeping Mask (HK$215) for all skin types offers an invisible "moisture wrap" of hydro ion mineral water, hunza apricot and evening primrose root extracts. New York-based facial expert Ling formulated the Ginseng Therapy Moisture Mask (HK$550; The Spa at Four Seasons Hotel, Central), which promises to soothe irritations and revive skin. Clarins offers the HydraQuench Cream Mask for dry skin (HK$360) while La Mer has an Intensive Revitalizing Mask (HK$1,500) that works its magic in just eight minutes. Just be sure to transfer your precious product into a travel-size container if it comes in larger packaging, or risk being arrested for air rage when they try to confiscate it. Remember that a mask is only one part of the skin-care regimen required for travel. You will still need to cleanse, tone and moisturise in the air.